Type species: Dentalium trachea Montagu, 1803 (by subsequent designation, Gray 1847: 203) from the Atlantic coasts of Europe, the Mediterranean Sea and northwestern Africa.

Caecum chinense de Folin, 1868: 80, pl. 9, figs 3, 4.

Caecum chinense: Albano & Pizzini 2011: 3–5, fig. 2A–H, J.

Caecum chinense: Pizzini et al. 2013: 29–30, fig. 12K–N.

Type locality: Near Deux Freres, China Seas [VIETNAM].

Type material examined: Lectotype (MNHN-IM-2000-24905) selected by Pizzini et al (2013: 29, fig. 12L). Material examined: SOUTH AFRICA: KwaZulu-Natal: 1 sh, Stn ZO4, off Cape St. Lucia (28°31.8′S 32°26.9′E), -76–80 m, coarse sand with mud, dredged R.V. Meiring Naudé, NMDP, 12.vi.1988 (NMSA E5196); 1 sh, Leadsman Shoal, Raggie Reef, -8–14 m, a mixed algal and coral reef, 1–2 km N of Leven Point, sorted from stone washings (NMSA E2726); 5 sh, Mapelane (NMSA E1662); 1 sh, off Richards bay, shallow dredgings, viii.1986 (JPM); 13 sh, Mapelane, S of St. Lucia, iv. 1981 (JPM 2116); 6 sh. Mission Rocks, N of St. Lucia, v.1989 (JPM); 86 sh, off St. Lucia Lighthouse, -50 m, ex C.S.I.R. Water Res. (NMSA A6212); 7 sh, off Richards bay, -50 m, fine quartzite, broken shell, ex C.S.I.R. Water Research (NMSA A6071); 2 sh, Aliwal Shoal, off Scottburgh, -10 m, sand and reef debris, hand-dredged D. Herbert 4.iv. 1992 (NMSA S8217); 1 sh, Aliwal Shoal, off Scottburgh, ± -16 m depth, hand-dredged sand (NMSA S5922); 2 lv and 1 sh, Aliwal Shoal (off Umkomaas), -27 m, silt from between rocks, dived G. Smith, don. J.P. Marais, iii.1988 (NMSA E1669); 1 sh, Richards bay, sand from harbour dredger (NMSA E1667); 1 sh, Aliwal Shoal, -9–15 m depth (NMSA E6166); 79 sh and 2 fragments, Durban Bay, shallow dredgings (NMSA E1019); 4 sh, Landers Reef (off Park Rynie), -30 m, slightly muddy sand (NMSA E1668); 2 sh (worn), Aliwal Shoal, off Scottburgh, -10–20 m, sand (NMSA S6743); 2 lv, Aliwal Shoal, off Scottburgh, -20 m ca., hand-dredged sand (NMSA S7902); 1 lv. Aliwal Shoal, off Scottburgh. ± -14 m (NMSA S6160); 14 sh, Aliwal Shoal, off Umkomaas area, -27 m, SCUBA, i.1988 (JPM); 1 sh, Landers Reef, off Scottburgh area, -45 m depth, SCUBA, iv.1988 (JPM); 1 lv and 9 sh, Durban Bay, shallow dredgings (JPM 2118); 84 sh, Durban Bay, shallow dredgings, sand (NMSA A5423); 2 sh, T. O. Strand, 2 km N of Port Edward (NMSA E1661); 5 sh (subadult). Leisure Bay, Port Edward, beach (JPM 2411); Eastern Cape: 1 sh, Mzamba, beachdrift, leg. R. Kilburn & D. Herbert 12–30.v.1986 (NMSA W9662); 5 sh, Mzamba (NMSA E1663); 23 sh, Mzamba, near Natal border (JPM); MOZAMBIQUE: 2 sh, sandbank S of Santa Carolina, Bazaruto Archipelago, in beach drift (NMSA G6534); PHILIPPINES: Palawan Is.: 4 sh. Meara I., 15 m (MP); 3 sh. Monoa Bay, 11 m(MP). Doubtful: SOUTH AFRICA: Western Cape: 1 lv (juv). Walker's Point, W of Knysna, leg. J.P. Marais iii.1991 (NMSA W9663).

Distribution: Indo-West Pacific; this species was collected in several stations along the eastern coast of South Africa (Fig. 3). Its occurrence on the southern coast needs confirmation.

Caecum subquadratum Carpenter, 1859: 433.

Caecum subquadratum: Tryon 1886: 216.

Caecum subquadratum: Hedley 1914: 293, pl. 18, fig. 67.

Caecum subquadratum: Pizzini & Raines 2011: 28, fig. 3H.

Type locality: SOUTH AFRICA: Port Elizabeth, here amended (see under remarks).

Type material examined: Lectotype herein selected (NHMUK 1858.12.9.13, Fig. 21E), glued on a small glass slide labelled by the author with white ink and a paper label, specifying the origin from Bean's colin (Fig. 21F).

Material examined: SOUTH AFRICA: Western Cape. 4 lv and 35 sh, Langebaan Lagoon, Saldanha Bay, xii.1987 (JPM); 1 lv and 4 sh (1 juv), Saldanha Bay, Langebaan Lagoon, grit washed up on sandy beach, leg. J.P. Marais xii.1987 (NMSA E1489); 1 lv and 1 sh, Hermanus (between False Bay and Cape Agulhas), v.1990 (JPM); 1 lv with operculum in a small glass vial, Walker's Bay, W of Knysna, iii.1991 (JPM); 1 lv and 1 sh. Walker's Point, W of Knysna, leg. J.P. Marais iii.1991 (NMSA S3729); KwaZulu-Natal: 1 sh, Leisure Bay, Port Edward, beach, iii.1986 (JPM).

Original description: “33 ? Caecum subquadratum, n. s.

? Caecum (Fartulum) t. elongata, minima, laevi, haud nitente; apertura haud contracta; septo submamillato, subungulato; margine laterali extante, supra satis convexo, lateribus rectis, parallelis; apice obtusissimo, lato, ad latus quadrato: operculo? … Long. .068, lat. .009-.012”

Additional description: Tube cylindrical, slender, slightly arched, whitish to transparent, in beached specimens often with alternating white and semitransparent bands, without sculpture. Aperture simple, sometimes with a barely visible swelling. Surface dull, smooth, featureless. Septum opaque, dome-shaped, very protruding. Mucro nail-like, rotated toward the right side, as high as the septum. When viewed from the right side the septum shows a subquadrate outline, while in ventral view it is bigibbous. Periostracum colourless. Juveniles are similar to the adults, and are distinguished by the subcylindrical and more arched tube, and by the less protruding septum and proportionally higher mucro which shows a more rounded lateral outline. Larval stage unknown. Operculum thin, corneous, circular, multispiral, composed of a central nucleus surrounded by a tight spiral of 4–5 whorls. External side slightly concave, internal side with a raised central disk (Fig. 1C).

Length: 1.6–1.9 mm.

Distribution: Southwestern to eastern coast of South Africa, from Saldanha to Port Edward (Fig. 3).

Remarks: Although the type locality of this species seems to be clearly indicated, i.e. Port Elizabeth, both the synopsis at the end of Carpenter's paper (1859: 443) and the original label of the lectotype refer to Australia (Fig. 21F). However, there is no toponym that refers to a Port Elizabeth in Australia. Conversely, a well-known Port Elizabeth exists in South Africa, hence one can suspect some confusion by Carpenter. Nevertheless in the introduction of his paper, Carpenter (1858: 417) clearly states that he could not find any Caecum species “at the Cape, or at Port Natal [today Durban]”, so one can deduce that he did not examine any Caecidae from South Africa. Moreover, C. subquadratum is the only Australian species reported in his paper. This ambiguity was also noticed by Hedley (1914), who reported a drawing of the lectotype but no Australian records. Furthermore, there is no specimen in either the AMS or WAM collections ascribable to subquadratum. Despite the uncertainty of the type locality, C. subquadratum is a well-defined species, characterized by a slender, cylindrical tube and by the squared profile of the septum in lateral view, while in ventral view it is more or less bimamillated. South African specimens perfectly fit the lectotype, except for the length of the tube. In fact, some populations are notably longer than the lectotype, suggesting that it is a subadult shell. On the basis of the available information the type locality of C. subquadratum is here amended as: SOUTH AFRICA: Port Elizabeth.

Etymology: Derived from the type locality (Cape Morgan) and used as a noun in apposition.

Description: Tube small, subcylindrical, proportionally thick, whitish, smooth. Aperture slightly oblique toward the ventral side, showing a well-developed swelling followed by a contraction and finally by a very small ring. Surface smooth, dull, without microsculpture. Septum opaque, slightly protruding over the cutting plane, with a sharp, nail-like mucro directed toward the right side, giving a dome-shaped outline to the septum when viewed from the side. Early stages and operculum unknown.

Length: 1.6–1.8 mm.

Type locality: SOUTH AFRICA: Eastern Cape: Agulhas Bank, off Cape Morgan Lighthouse, -100 m.

Holotype (Figs 2A–C, 22D, 23D): SOUTH AFRICA: Eastern Cape: sh, Agulhas Bank, off Cape Morgan Lighthouse, -100 m, broken coral + shell, don. A. Connell, 1977, (NMSA B7132/T3377), length 1.66 mm, min. diam. (posterior end) 0.22 mm, diam. in the middle of the tube 0.30 mm, max. diam. (apertural end) 0.34 mm.

Paratypes: 6 sh, same data as holotype (NMSA W9676/T3378).

Comparative material examined: C. campanulatum Raines & Pizzini, 2005, holotype (LACM 3027); C. chinense de Polin, 1868, lectotype (MNHN-IM-2000-24905); C. dakuwaqa Pizzini, Raines & Vannozzi, 2013, holotype (MNHN-IM-2000-24843); C. subquadratum Carpenter, 1859, lectotype (NHMUK 1858.12.9.13, Fig. 21E); C.fijiense Pizzini, Raines & Vannozzi, 2013, holotype (MNHN-IM-2000-24857).

Distribution: Currently known only front the type locality, Cape Morgan, north of East London (Fig. 3).

Remarks: Caecum morgan sp. n. strongly resembles C. subquadratum due to the lack of both sculpture and microsculpture, as well as a similar shape of the mucro. It can however be separated by the distinctly subcylindrical and more curved shape of the tube, and by the presence of a conspicuous swelling above the aperture, barely visible in C. subquadratum. In C. morgan sp. n. the septum is only somewhat emerging above the cutting plane. Conversely, in C. subquadratum the septum is more protruding, on the whole giving the mamillate-ungulate appearance pointed out by Carpenter (1859). Caecum morgan sp. n. resembles C. gofasi Pizzini & Nofroni, 2001 in general aspect, but the latter has a dorsal spatulate mucro and shows a distinct worm-like microsculpture absent in the new species. Moreover, C. morgan sp. n. is also similar to C. campanulatum Raines & Pizzini 2005, C. dakuwaqa, and C. fijiense (both Pizzini, Raines & Vannozzi, 2013), having the same bell-shaped aperture, but in these species the septum is dome-shaped without any mucro. Additionally, C. morgan sp. n. differs from C. dakuwaqa by the lack of the exasperate torsion of the tube occurring in the latter. Caecum morgan is also similar to C. musorstomi Pizzini, Raines & Vannozzi, 2013, from which it can be separated by the smooth surface without sculpture, and microsculpture and by a different orientation and shape of the mucro.

Etymology: From Latin name auster (the south) and the adjective africanus (African), meaning South African.

Description: Tube subcylindrical, slender, with a slight dextral torsion, rather straight in the adapical portion, more or less curved in the abapical half. Tube smooth, somewhat glossy, colourless. Aperture oblique with a rather strong swelling, preceded by a white band. Surface with only oblique growth lines. Septum opaque, protruding, with a variable outline, often from flat to S-shaped, more rarely convex, with a dorsal naillike mucro, somewhat rotated toward the right side, generally more protruding than the septum. Macula large with a frosted appearance, more or less symmetrical, elongated, placed in the middle of the ventral side, posteriorly bilobed, anteriorly narrower and fading. Juveniles rather different from adults, distinctly conical and showing a clear dextral torsion. Larval stage not determined with certainty, probably with a multispiral protoconch. Periostracum light brown. Operculum, corneous, circular, multispiral, composed by a central nucleus surrounded by a tight spiral of about 4 whorls. External side slightly concave, internal side with a raised nucleus.

Length: 1.7–2.9 mm.

Type locality: SOUTH AFRICA: Eastern Cape: Algoa Bay.

Holotype (Figs 4A–C, 22F, 23F): lv, SOUTH AFRICA: Eastern Cape: Algoa Bay, vi.1976 (W9655/T3349). length 2.11 mm, min. diam. (posterior end) 0.32 mm, diam. in the middle of the tube 0.41 mm, max. diam. (apertural end) 0.44 mm.

Paratypes: SOUTH AFRICA: Western Cape: 18 lv and 166 sh (9 juv), Knysna, Gericke Point, Sedgefield (NMSA W9659/T3352); 18 lv and 245 sh (23 juv), Walker's Point, W of Knysna, leg. J.P. Marais iii. 1991 (NMSA W9656/T3351); 1 sh (worn), Cape Overberg, Onrus R., ± 5 km W of Hermanus, in sand under rock in sheltered rockpool (NMSA S2626/T3879); 1 sh, Hermanus (between False Bay and Cape Agulhas), v.1990 (JPM); 1 lv and 24 sh, Walker's Bay, W of Knysna, iii.1991 (JPM); 3 sh, False Bay, Miller's Point, purch. Mrs C.M. Connolly i.1974 (NMSA A1879/T3877); Eastern Cape: 5 lv and 47 sh (1 with two attached stages), same data as holotype (JPM); 4 lv (with opercula in small glass vials), Algoa Bay, off Cape Recife, -25 m, debris from bryozoan colony, dived B. Hayes, xii.1992 (NMSA V115/T3353); 6 sh (1 juv), Algoa Bay, Humewood sand, don. F. Graeve, v.1977 (NMSA A5589/T3350); 2 lv and 22 sh, Fish R. mouth (between Port Alfred and East London), iv.1978 (JPM 2117); KwaZulu-Natal: 1 lv and 1 sh, Aliwal Shoal, off Umkomaas, -27 m, silt from between rocks, dived G. Smith, don. J.P. Marais iii.1988 (NMSA E1670/T3878); 1 sh, Aliwal Shoal, off Scottburgh, -25–27 m, sand and reef debris (NMSA S7078/T3880).

Additional material examined: SOUTH AFRICA: Western Cape: 1 sh, Witsand, Brede R. mouth, St. Sebastian Bay, beachdrift, leg. C.D. Quickelberge 2.ix.1982 (NMSA E2395); 1 sh, Knysna, Gericke Point, Sedgefield (NMSA W9671); Eastern Cape: 3 lv and 5 sh, Fish R. mouth, south side (NMSA B4185); 74 lv, Algoa Bay, W9671 ); Eastern Cape. 3 lv and 5 sh, Fish R. mouth, south side (NMSAB4185); 74 lv, Algoa Bay, off Cape Recite, -25 m, debris from bryozoan colony, dived B. Hayes, xii.1992 (NMSA W9685); 17 sh, Port Alfred, leg. J. Huff (J. Huff colin, ex Albany Museum, 1980, NMSA E1666).

Comparative material examined: C. variegatum de Folin, 1867, syntype (MNHN-IM-2000-25783, Fig. 21A–D); C. macrum van der Linden & Moolenbeek, 2000; SENEGAL: 2 sh, Charbonnier, petite épave, -34 m, fond sable coquiller légerement vaseux, leg. J. Pelorce (MP); 1 sh, Somone, -7 m, sable sur rochers plats avec curvettes sable, leg. J. Pelorce (MP).

Distribution: Southern and eastern coasts of South Africa, from False Bay to Aliwal Shoal, south of Durban (Fig. 7).

Remarks: This species is rather variable in terms of dimensions and curvature of the tube, which is, however, always straighter in the middle portion. The most similar species to Caecum austrafricanum is C. variegatum de Folin, 1867 (Fig. 21A–D). Caecum variegatum was originally described by de Folin from Hong Kong and recently reported by Hughes (1985) for the same locality, while no other finding is reported in the literature. This species seems to be absent from Australia as well (unpublished data). The main differences concern the absence of apertural swelling in C. variegatum and the shape of the mucro, which is narrow and spatuliform in C. variegatum, while in C. austrafricanum it is broad and not distinct from the septum when observed in ventral view (Figs 21D, 23F, G).

Caecum austrafricanum resembles C. macrum van der Linden & Moolenbeek, 2000 (Fig. 25R) described from western Africa, from which it can be distinguished by the slenderer and thicker tube, the aperture provided with a well-developed swelling not observed in C. macrum and by the different shape of the septum. Moreover, the macula in C. macrum is different, being shorter and heart-shaped (Fig. 24A, H).

Etymology: Derived from the type locality.

Description: Tube subcylindrical, with a slight dextral torsion, evenly arched. Tube smooth, glossy, colourless, semitransparent. Aperture with a barely visible swelling, strongly oblique toward the ventral side, preceded by a white band. Surface with only fine oblique growth lines. Septum smooth, dome-shaped, protruding, with an ear-like mucro directed halfway between the dorsal and the right side. Macula large, with a frosted appearance, formed by two oblong bands fused in the middle. Juveniles rather similar to the adults, showing a narrower and more arched shape of the tube. Periostracum light brown. Operculum flat with a raised internal nucleus and internally thickened edge. Outer side showing a spiral of about three whorls. Larval stage unknown.

Length: 1.2–1.9 mm.

Type locality: SOUTH AFRICA: Western Cape: Knysna, Gericke Point, Sedgefield.

Holotype (Figs 5A–C, 22I, 23I): SOUTH AFRICA: Western Cape: lv, Knysna, Gericke Point, Sedgefield (NMSA S7625/T3362), length 1.6 mm, min. diam. (posterior end) 0.31 mm, diam. in the middle of the tube 0.36 mm, max. diam. (apertural end) 0.37 mm.

Paratypes: SOUTH AFRICA: Western Cape: 1 lv and 6 sh, same data as holotype (NMSA W9673/T3364); 2 lv and 6 sh (1 juv). Walker's Point, W of Knysna, leg. J.P. Marais iii.1991 (NMSA W9672/T3363).

Doubtful: SOUTH AFRICA: Western Cape: 1 sh (broken), Walker's Bay, W of Knysna, iii.1991 (JPM).

Comparative material examined: C. macrum van der Linden & Moolenbeek, 2000, SENEGAL: 2 sh, Charbonnier, petite épave, -34 m, fond sable coquiller légerement vaseux, leg. J. Pelorce (MP); 1 sh, Somone, -7 m, sable sur rochers plats avec curvettes sable, leg. J. Pelorce (MP).

Distribution: Known with certainty only from Knysna (Fig. 7).

Remarks: This species clearly resembles Caecum austrafricanum sp. n. However, there are some consistent differences that set specimens of this species apart from the hundreds of C. austrafricanum specimens found in the same sites. In fact, C. knysnaense sp. n. is smaller and shows an aperture which is more oblique by ca. 10° and lacks a clear swelling. Additionally, the septum of C. knysnaense is convex while in C. austrafricanum it is typically flat or S-shaped. Also the mucro and the general aspect of the tube are different.

Caecum knysnaense also strongly resembles C. macrum van der Linden & Moolenbeek, 2000 (Fig. 25R), from which it can be distinguished by the different shape of the mucro and by the more oblique aperture. Also the macula is different, being shorter and heart-shaped in C. macrum (Fig. 24B, H).

Etymology: From the Latin adjective intortus (= twisted) due to the twisted shape of the tube.

Description: Tube cylindrical, only slightly arched. The tube shows a clear dextral torsion. Tube smooth without sculpture, colourless, dull. Aperture preceded by a slight swelling. The aperture is oblique in both ventral and lateral direction, being contracted on the left side. Surface with only oblique, fine growth lines. Septum dome-shaped, granulated, with a broad nail-like mucro directed toward the right side. Macula large, ill-defined, expanded, with a frosted appearance, clearly displaced to the left side. Juveniles rather different from adults, more conical and showing a clear dextral torsion. Larval stage not determined with certainty, probably with a multispiral protoconch. Periostracum light brown. Operculum, corneous, circular, multispiral, composed of a small central nucleus surrounded by an open spiral of 6–7 whorls. External side flat, internal side with a concave nucleus.

Length: 1.9–2.6 mm.

Type locality: SOUTH AFRICA: Western Cape: Walker's Point, west of Knysna.

Holotype (Figs 6A–C. 22J. 23J): SOUTH AFRICA: Western Cape. sh. Walker's Point. W of Knysna. leg. J.P. Marais iii. 1991, (NMSA W9668/T3358), length 2.12 mm, min. diam. (posterior end) 0.38 mm, diam. in the middle of the tube 0.45 mm, max. diam. (apertural end) 0.49 mm.

Paratypes: SOUTH AFRICA: Western Cape. 2 sh, Hermanns (between False Bay and Cape Agulhas), v.1990 (JPM); 1 lv, Walker's Bay, W of Knysna, iii.1991 (JPM); 4 sh, Knysna, Gericke Point, Sedgefield (NMSA W9670/T3361); 2 lv and 8 sh, same data as holotype (NMSA W9669/T3360); Eastern Cape. 1 sh, Algoa Bay, vi.1976 (JPM); 1 sh, Algoa Bay, Humewood sand, don. F. Graeve v.1977 (NMSA W9667/T3359).

Additional material examined: SOUTH AFRICA: Eastern Cape. 1 sh (juv). Port Alfred, (J. Hutt colln, ex Albany Museum. 1980) (NMSA W9666).

Comparative material examined: C. crassum de Folin, 1870, lectotype (MNHN-IM-2000-27586) selected by Linden & Moolenbeek (2000: 82, fig. 3); SENEGAL: 8 sh, Gambia, -7 m (F. Swinnen colln, Lommel, Belgium); MAURITANIA: 1 lv + 34 sh. Banc d'Arguin, intertidal, leg. E. Rolán (MP); GABON: 2 sh (1 juv)(MP).

Distribution: Southern coast of South Africa from Hermanus to Algoa Bay (Fig. 7).

Remarks: The species most similar to Caecum intortum is C. crassum de Folin, 1870 (Fig. 25S, T), an endemic species of western African coasts (from West Sahara to Ghana), having in common the general shape of the tube and the typology of the septum, but differing in the smaller dimensions and in the exasperate torsion of the tube not observed in C. crassum. Additionally, C. intortum shows a different shape of the macula, which is also clearly displaced toward the left, and lacks the longitudinal microsculpture that is observed in C. crassum (van der Linden & Moolenbeek 2000). Caecum intortum resembles both C. austrafricanum sp. n. and C. knysnaense sp. n., from which it can be separated by a wider tube, a more cylindrical shape, a clearly twisted tube and the position of the mucro, lateral rather than dorsal.

Etymology: From the Latin adjective incisus (incised) due to the presence of collabral incisions that are observed throughout the tube.

Description: Tube cylindrical, evenly arched, smooth without sculpture. Both tube and septum are semitransparent, colourless and glossy. Aperture simple, without any swelling or varix, even and not oblique. Microsculpture comprised of collabral incisions which define flat rings. These incisions, spaced by about 2–3 µm apart and rather regular in young specimens, tend to become irregular in adults. This feature causes the appearance of the shells, glossy and shining in the former, to become milky and opaque in the latter. Septum smooth, dome-shaped, with an ear-like mucro rotated toward the right by about 45°. The septum shows some more or less parallel grooves arranged like waves coming from the tip of the mucro. In terms of both curvature of the tube and shape of the aperture juveniles are quite similar to the adults, and are distinguished by the smaller diameter and the more regular microsculpture. Periostracum colourless, dull. Larval stage and operculum unknown.

Length: 1.6–1.8 mm.

Type locality: SOUTH AFRICA: Western Cape: Knysna, Gericke Point, Sedgefield.

Holotype (Figs 8A–C. 22L. 23L): SOUTH AFRICA: Western Cape. sh. Walker's Point W of Knysna. leg. J.P. Marais iii.1991 (NMSA S3728/T3355), length 1.69 mm, min. diam. (posterior end) 0.29 mm, diam. in the middle of the tube 0.33 mm, max. diam. (apertural end) 0.36 mm.

Paratypes: SOUTH AFRICA: Western Cape. 4 sh, same data as holotype (NMSA W9660/T3356); 8 sh, Knysna, Gericke Point, Sedgefield (NMSA W9661/T3357); KwaZulu-Natal: 1 sh, Aliwal Shoal, -9–18 m, dived D. Herbert 21.xii. 1986 (NMSA D5269/T3881); 1 sh (juv). Aliwal Shoal. off Umkomaas area. -27 m. SCUBA, i.1988 (JPM).

Additional material examined: SOUTH AFRICA: Eastern Cape. 2 sh (1 broken), Mzamba, near Natal border, vii.1976 (JPM 2119); KwaZulu-Natal: 1 sh (lost), Aliwal Shoal (off Umkomaas), -27 m, silt from between rocks (NMSAE1670); 1 lv, Landers Reef, off Scottburgh Area, -45 m, SCUBA, iv.1988 (JPM). Comparative material examined: C. sinuatum de Folin, 1879, BORNEO, syntype (MNHN-IM-2000-27585); C. inhacaense Albano & Pizzini, 2011, MOZAMBIQUE: Inhaca I., holotype (MZB 15000).

Distribution: Southern and eastern coasts of South Africa from Knysna to Aliwal Shoal (Fig. 11).

Remarks: The microsculpture exhibited by C. incisum is unique among South African Caecum species. This kind of microsculpture is shown by C. sinuatum de Folin, 1867 described from Borneo. However, de Folin's species is quite different front C. incisum, showing a very slender and slightly arched tube, a different shape of the septum and a strong constriction before the aperture. Caecum incisum occurs sympatrically with C. austrafricanum sp. n., C. intortum sp. n. and C. inhacaense, from which it can be distinguished by the even curvature of the tube, the lack of apertural swelling, the presence of incised growth lines defining flat rings throughout the tube, the lack of the macula and the different shape of the mucro.

Etymology: Named after Johan Marais (South Africa), who with the large amount of collected specimens greatly contributed to the knowledge of South African Caecidae.

Description: Tube small, slightly subcylindical, more arched toward the aperture. Both tube and septum are semitransparent, colourless and glossy. The surface shows a microsculpture composed of shallow worm-like grooves interrupted by irregularly-set growth lines. At higher magnification, the microsculpture is composed of very small pits with a diameter of about 1 µm arranged in longitudinal rows. Septum vitreous, smooth, dome-shaped, very protruding, with an indistinct mucro directed toward the right side. The septum shows some more or less parallel grooves arranged like waves coming from the tip of the mucro. Juveniles quite similar to the adults, and are distinguished by the more tapered shape, the smaller diameter and the less protruding septum. Larval stage and operculum unknown.

Length: 1.6 mm.

Type locality: SOUTH AFRICA: Western Cape: Knysna, Gericke Point, Sedgefield.

Holotype (Figs 9A–C. 22N. 23N. 26E): SOUTH AFRICA: Western Cape. sh. Knysna. Gericke Point. Sedgefield (NMSAW9765/T3376), length 1.64 mm, min. diam. (posterior end) 0.26 mm, diam. in the middle of the tube 0.32 mm, max. diam. (apertural end) 0.32 mm.

Paratype: SOUTH AFRICA: Eastern Cape: sh (juv). Fish R. mouth (between Port Alfred and East London), iv.1978 (JPM 2117).

Comparative material examined: C. incisum sp. n.

Distribution: Only known from the type locality and from Fish River mouth (between Port Alfred and East London) (Fig. 11).

Remarks: This species strongly resembles C. incisum sp. n. which is found in sympatry and with which it is easily confused. It can be distinguished by the slenderness of the tube, the absence of ring-like growth lines, the presence of longitudinal microsculpture and by the different shape of the septum, which is more protruded and with a parabolic outline.

Etymology: Named after the late Leila Zitelli, second author's mother.

Description: Tube rather large, cylindrical, colourless and glossy, semitransparent, evenly arched, sculptured by very fine, slightly oblique rings, more evident in the abapical half, separated by narrower interspaces. Aperture simple, contracted, slightly oblique toward the ventral side. Surface grooved by gross, shallow, worm-like incisions visible at low magnifications especially in the adapical half. Septum dome-shaped, opaque, smooth, very protruding. Mucro ear-like, of variable height with respect to the septum, positioned at a variable angle between the dorsal and the right side. Surface of the septum with orange-peel aspect. Sparse, irregular grooves arranged like waves coming from the mucro are often visible on the septum. Macula small, heart-shaped, hardly visible, transparent, slightly displaced to the left side. Periostracum light brown, dull, easily lost, sculptured by fine longitudinal worm-like grooves. Juveniles quite similar to the adults, having the same morphology of the aperture, sculpture and microsculpture and are distinguished by the smaller diameter, the more curved tube, the less defined rings and by the slightly less protruding septum. Larval stage unknown. Operculum thin, corneous, circular, multispiral, composed by a small central nucleus surrounded by an initially tight spiral of 7–8 whorls. External side slightly concave, internal side with a slightly convex nucleus.

Length: 2.5–3.2 mm.

Type locality: SOUTH AFRICA: Eastern Cape: Mzamba.

Holotype (Figs 10A–C, 22P, 23P): SOUTH AFRICA: Eastern Cape: sh, Mzamba, beach drift, leg. R. Kilburn & D. Herbert 12–30.V.1986 (NMSA D3032/T3374), length 3.1 mm, min. diam. (posterior end) 0.51 mm, diam. in the middle of the tube 0.6 mm, max. diam. (apertural end) 0.62 mm.

Paratypes: SOUTH AFRICA: Eastern Cape. 7 lv and 26 sh, Mzamba, near Natal border, vii.1976 (JPM 2119); 2 lv and 6 sh, same data as holotype (NMSA W9674/T3375); 1 lv, Mbotyi, beach drift, leg. R. Kilburn. D. Herbert v-vi.1985 (NMSA C8454/T3885); KwaZulu-Natal 2 lv. Mapelane. S of St. Lucia, iv.1981 (JPM 2116); 1 lv. off Richards bay, shallow dredgings, viii.1986 (JPM); 2 sh, off Durban Bluff. -18–22 m. fine sand, leg. RK, RF 1983 (NMSA E981/T3883)1 1v and 3 sh (1 broken). Mission Rocks. N of St. Lucia, v.1989 (JPM); 1 lv and 2 sh (1 broken, 1 with two attached growth stages), Mapelane. leg J. Marais iv.1981 (NMSA B4607/T3882); 1 lv. Umtamvuna R. mouth. beach-drift. leg. J.P. Marais vi.1996 (NMSA V3999/T3884).

Comparative material examined: C. inflatum de Folin, 1869, lectotype (MNHN-IM-2000-24915) selected by Pizzini et al. (2013: 30, fig. 12P–R); C. attenuatum de Folin, 1880, lectotype (NHMUK 1887.2.9.2315) selected by Pizzini et al. (2013: 3, fig. 90, P); C. cooki Pizzini & Raines, 2011, holotype (MNHN-IM-2000-23124); C. incisum sp. n.; C. inhacaense Albano & Pizzini, 2011, holotype (MZB 15000).

Distribution: Eastern coast of South Africa from Mbotyi (south of Port Edward) to St. Lucia (Fig. 11).

Remarks: Caecum leilae resembles C. inflatum de Folin, 1869 and C. attenuatum de Folin, 1880 which show a similar annulated sculpture, but the septum is different, with a larger and ill-defined mucro in C. inflatum and with a triangular outline in C. attenuatum.

Caecum leilae can also be compared with the Indo-West Pacific species C. cooki Pizzini & Raines, 2011 with which it shares the shape of the ear-like mucro, but shows no sculpture and a different shape of the aperture as well.

Juveniles of C. leilae can be confused with C. incisum and C. inhacaense. However, C. leilae can be distinguished by the different sculpture (obsolete rings in leilae, incised collabral grooves defining flat rings in incisum) and by the mucro (broader in C. incisum and by the presence of the longitudinal microsculpture, while the latter shows a different shape of the mucro and lacks the regular annular sculpture crossed by the longitudinal microsculpture occurring throughout the tube that is typical of C. leilae). Moreover, the maculae in C. leilae and C. inhacaense are different in both shape and colour (heart-shaped and transparent in the former, roundish to chevron-shaped and opaque white in the latter) (Fig. 24E–G).

Caecum inhacaense: Albano & Pizzini 2011: 5, 6, fig. 3A–C, E.

Type locality: MOZAMBIQUE: Ilha de Inhaca, Barreira Vermelha.

Type material examined: MOZAMBIQUE: holotype (MZB 15000).

Material examined: SOUTH AFRICA: Eastern Cape: 10 sh, Mzamba, near Natal border, vii.1976 (JPM 2119); 1 lv, Mtentu R. Mouth, iv.1982 (JPM 2414);KwaZulu-Natal: 1 sh, Aliwal Shoal, off Umkomaas area, -27 m. SCUBA. 1.1988 (JPM); 2 sh (1 juv). Stn Z04. off Cape St. Lucia (28°31.8′S 32°26.9′E), -76–80 m. coarse sand with mud, dredged R.V. Meiring Naudé, NMDP, 12.vi.1988 (NMSA W9665).

Doubtful: SOUTH AFRICA: Western Cape: 1 sh. Knysna. Gericke Point. Sedgefield (NMSA W9679); Eastern Cape: 1 sh. Algoa Bay, St. Croix I., East. -50–60 ft. coarse sand, dived A. Connell, don. C.S.I.R. Water Res. 1977 (NMSA A6770); 1 sh. Mzamba. beachdrift. leg. R. Kilburn & D. Herbert 12–30.5.1986 (NMSA W9664).

Comparative material examined: C. incisum sp. n.

Original description: “Tube cylindrical, smooth, crossed only by fine growth striation. Septum mucronate, turned to right side by about 30° and protruding over the cutting plane. Mucro has the form of a small flattened ball, almost obsolete in juvenile specimens. Dorsal margin of mucro strongly convex, while its ventral margin slightly S-shaped and inflated near the cutting plane. Aperture circular, weakly ringed and slightly contracted. Juveniles have more slender shell, and aperture lip thin and fragile. Colour whitish. Operculum and soft parts morphology unknown.

Holotype dimensions: length 1.4 mm, diameter 0.3 mm.”

Additional description: Tube cylindrical, colourless, whitish in beached specimens, the last portion bent toward the ventral side. No sculpture. Aperture slightly flaring and oblique. Surface with only oblique growth lines. Septum opaque, dome-shaped, variably protruding. Mucro ill-defined, placed on the right side, typically higher than the septum, dorsally protruding with a resulting concave outline just above the cutting plane. Macula white, small, roundish to chevron-shaped, located in the middle of the ventral side of the tube, slightly displaced toward the left side (Fig. 24G). Periostracum light brown, somewhat glossy, persistent.

Length: 1.2–1.6 mm.

Distribution: Originally described from south of Mozambique, its distribution is herein extended to the eastern coast of South Africa up to the Mtentu River (Fig. 13). Its occurrence on the southern coast needs confirmation.

Remarks: Caecum inhacaense resembles the sympatric C. incisum sp. n. as regards to the general proportions, but it can be distinguished by the presence of a white macula, the lack of incised collabral grooves, the presence of a slight apertural swelling and the mucro that forms a lower angle with respect to the ventral-dorsal direction.

Caecum inhacaense is a rather elusive species due to the lack of striking characters. A careful examination of South African specimens revealed that the bending of the last quarter of the tube and the shape of the mucro are useful characters. In particular, the mucro is neither nail- nor ear-like as in other species with similar appearance, but has a convex outline, shaped like a flattened ball that protrudes dorsally, leaving a concave region just above the cutting plane. Also the presence of a small, white macula is a useful character.

Material examined: SOUTH AFRICA: KwaZulu-Natal: 1 lv, Kosi Bay, main reef, 1–4 km S of estuary mouth, stone surfaces, ± -15 m, dived D. Herbert, 4.V.1990 (NMSA S2869).

Description: Tube evenly arched, colourless, semitransparent. Surface crossed by coarse growth lines, assuming the form of small, hardly visible rings toward the aperture. The tube widens before the aperture, forming a ring-like swelling, which is crossed by some ill-defined annulations, after which it contracts again, ending with a very small ring. Microsculpture composed by a fine worm-like striation. Septum dome-shaped, protruding, with a low dorsal mucro. Periostracum colourless. Operculum thin, flat, corneous, multispiral, internal side with a slightly raised nucleus sorrounded by a tight spire of 7 whorls, external side with a concave nucleus. Length: 1.9 mm.

Distribution: Caecum gulosum is found in the eastern Pacific Ocean (Pizzini et al. 2013). A single specimen tentatively attributed to this species was found on the eastern coast of South Africa (Fig. 13). The presence of Caecum gulosum in South Africa needs confirmation.

Material examined: SOUTH AFRICA: KwaZulu-Natal: 2 sh (worn), Landers Reef, off Scottsburgh area, 45 m. SCUBA (JPM).

Comparative material examined: Caecum musorstomi. holotype (MNHN-IM-2000-24921) (Pizzini et al. 2013: fig. 12G–I); PHILIPPINES: 73 sh. Meara Is. (Palawan I.), 15 m. leg. M. Oliverio 10.vi.1996 (MP).

Distribution: Caecum musorstomi occurs in the SW Pacific, Japan and Philippine Is. Two specimens tentatively attributed to this species were found on the eastern coast (Fig. 13). The presence of C. musorstomi in South Africa needs confirmation.

Remarks: Two worn specimens on the whole fitting Caecum musorstomi were found on the eastern coast of South Africa. However, attribution to this species is only tentative as both annular sculpture and longitudinal microsculpture are not clearly visible.

Caecum sepimentum de Folin, 1868: 84, pl. 6, fig. 7.

Caecum sepimentum var. arcuata de Folin, 1880: 809.

Caecum lilianum Hedley, 1903: 603, pl. 29, fig. 7.

Caecum maculata [sic] Habe, 1963: 236, fig. 2.

Caecum berberense Ladd, 1972: 22, 23, pl. 5, figs 11, 12.

Caecum septimentum [sic] Lightfoot, 1992: 1, 4, figs 2, 3.

Caecum gracile Sasaki, 2008: 169, fig. 9E, F.

Caecum sepimentum; Albano & Pizzini 2011: 6–9, fig. 4A–D.

Caecum sepimentum; Pizzini et al. 2013: 5–8, figs 8A–D, F, G, 19K, 20A–D.

Type locality: Mauritius I.

Type material examined: Lectotype (MNHN-IM-2000-24907) selected by Pizzini et al. (2013: 5, fig. 8D).

Material examined: SOUTH AFRICA: Eastern Cape: 1 sh, Mzamba, beachdrift, leg. R. Kilburn & D. Herbert 12–30.V.1986 (NMSA A6285); KwaZulu-Natal: 5 lv and 12 sh, Aliwal Shoal ± -16 m, hand-dredged sand (NMSA S5943); 5 lv and 39 sh, Landers Reef, off Scottburgh area, -33 m, SCUBA (JPM); 3 lv and 135 sh, Aliwal Shoal, off Umkomaas area, -27 m, SCUBA, i.1988 (JPM); 7 sh, Landers Reef, off Scottburgh area, -45 m, SCUBA, iv.1988 (JPM); 1 sh, Mission Rocks, N of St. Lucia, v.1989 (JPM); 5 lv and 19 sh, Aliwal Shoal, off Scottburgh, -25–27 m, sand and reef debris (NMSA S7186); 34 lv and 55 sh, Aliwal Shoal, off Scottburgh, -14 m, underwater pump (NMSA S8627); 6 lv and 1 sh, Aliwal Shoal, Cracker Reef, -23 m (NMSA E7168); 3 sh, Park Rynie, -50 m, coarse sand, 2–25.xi.1976, ex C.S.I.R. water Res. 1977 (NMSA B240); 2 lv and 9 sh, Aliwal Shoal, off Scottburgh, -10–20 m, sand (NMSA S6822); 3 lv and 5 sh (1 juv), Landers Reef (off Park Rynie), -30 m, slightly muddy sand (NMSA E1671); 1 sh, Landers Reef, -20–30 m, sorted from stone washings (NMSA E2317); 7 lv and 5 sh, Aliwal Shoal, -9–15 m (NMSA E6165); 7 lv (1 juv) and 5 sh, Aliwal Shoal, off Scottburgh, -10 m, sand and reef debris (NMSA S8247); 11 sh, off Sodwana Bay, sediment at base of drop-off in canyon, -46 m, Marine Geoscience Unit, 7.xii.1992 (NMSA V2626); 8 lv and 4 sh, Kosi Bay, main reef 1–4 km S of estuary mouth, -23–24 m, underwater pump (NMSA S2918); 16 lv and 47 sh, Leadsman Shoal, outer portion -24–26 m, sorted from stone washings (NMSA E2677); 2 lv, Leadsman Shoal, raggie reef, -8–14 m, a mixed algal and coral reef 1–2 km N of Leven Point, sorted from stone washings (NMSA E2725); 3 lv and 9 sh, Leadsman Shoal, outer portion, -25–28 m (NMSA E6929); 2 lv, Leadsman Shoal, -15 m, scrapings + broken down coral rubble (NMSA E2273); 1 lv and 8 sh, Stn ZB7, off Boteler Point (27°00.5′S 32°54.7′E), -50 m, coral rubble, dead Lithothamnium, R.V. Meiring Naudé. 6.6.1987 (NMSA E1588); 1 sh, Sodwana Bay, two-mile reef (outer edge), sorted from stone washings, -15–17 m (NMSA D5304); 5 sh, Stn ZA21, SE of Kosi R. mouth (26°55.2′S 32°55.0′E), -50 m, fine sand, dredged NMDP, 8.vi.1987 (NMSA E1516); 1 lv and 16 sh, between Bhanga Neck and Kosi Bay, reef off marker, 13 tan North, -13 m, hand-dredged sand (NMSA S3118); 1 sh, Stn ZM7, off Cape Vidal (29°07.1S 32°36.6′E), -145 m, medium sand, dredged, NMDP, 10.vi.1988 (NMSA E7550); 1 sh, Stn ZF8, off Hully Point (27°4′S 32 46.4′E), -40 m, fine sand, dredged, NMDP, 5.vi.1987 (NMSA E1658); 4 sh (worn), Stn ZK2, off Gipsy Hill (27°48.8′S 32°38.4′E), -50 m, dredged, NMDP, 8.vi.1988 (NMSA 4184); 1 sh (worn), Stn ZA19, off Kosi estuary (26°56.7′S 32°54.7′E), -50 m, coarse sand, shells, dredged, NMDP, 8.vi.1987 (NMSA E1630); 22 sh (worn), Stn ZO4, coarse sand with mud, dredged, NMDP, 12.vi.1988 (NMSA E5197); 1 lv and 2 sh, Sodwana Bay, two-mile reef, sorted from stone washings, -10–15 m (NMSA E769); 2 lv and 4 sh, Kosi Bay, main reef, 1–4 km S of estuary mouth, -20 m, underwater pump (NMSA S2526); 3 lv, off Kosi Bay, main reef, 1–2 km S of estuary, sorted from stone washings, -9–17 m (NMSA D9833); 1 sh, off Kosi Bay, main reef, 1–4 km S of estuary, -9–17 m (NMSA D9267); 1 sh, Stn ZN7, S.E. of Mission Rocks (28°17.5′S 32°34.2′E), -100 m, medium sand, dredged, NMDP, 11vi.1988 (NMSA E5191); 2 sh (worn), Stn ZK4, NE of Gipsy Hill (27°45.2′S 32°39.8′E), -110 m, sponge, stones, dredged, NMDP, 8.vi.1988 (NMSA E5204); 14 sh, Stn ZB 5, off Boteler Point (27°00.0′S 32°55.2′E), -70 m, coral rubble, dredged, NMDP, 6.vi.1987 (NMSA E1566); 2 lv and 21 sh, Stn ZN1, SE of Mission Rocks (28°17.5′S 32°32.6′E), -50 m, old coral rubble, Lithothamnium, dredged, NMDP, 10.vi.1988 (NMSA E6252); 2 sh, Stn ZK1, off Gipsy Hill (27°49.7′S 32°38.2′E). -47–50 m, fine sand, dredged, NMDP, 8.vi.1988 (NMSA E5663); 2 lv and 1 sh, between Bhanga Neck and Kosi Bay, reef off marker 13 North, -8 m, underwater pump (NMSA S2738); 2 lv and 1 sh, Leadsman Shoal, main portion of coral reef, -7–11 m (NMSA E6774); 12 lv and 11 sh, Kosi Bay, main reef, 1–4 km S of estuary mouth, -20–22 m, underwater pump (NMSA S2010); 14 sh, Stn ZE2 off Rock I. (27°17.2′S 32°48.0′E), -62 m, sandstone, coral, marine growths, dredged, NMDP, 5.vi.1987 (NMSA E1542); 1 sh, Stn ZN1, SE of Mission Rocks (28°17.5′S 32°32.6′E), -50 m, old coral rubble, Lithothamnium, dredged, NMDP, 10.vi.1988 (NMSA E7493); 46 sh, Stn ZK3, off Gipsy Hill (27°47.4′S 32°38.9′E), -65–70 m, broken shell, dredged, NMDP, 8.vi.1988 (NMSA E5893); 12 lv and 19 sh, Kosi Bay, main reef 1–4 km S of estuary mouth, -18 m underwater pump (NMSA S4252); 2 sh, Stn ZK6, off Gipsy Hill (27°48.9′S 32°38.4′E), -50 m, fine sand, dredged, NMDP, 8.vi.1988 (NMSA E7497); 7 sh, Stn Z15, NE of Leven Point (27°55.0′S 32°38.8′E), -250 m, coarse sand, dredged, NMDP, 9.vi.1988 (NMSAE5883); 1 sh, Stn ZM9, off Cape Vidal (28°08.3′S 32°36.9′E), -200 m, sponge rubble, dredged, NMDP, 11.vi.1988 (NMSA E5887); 1 sh, off Kosi Bay, main reef 1–2 km S of estuary, sorted from stone washings, -9–17 m (NMSA D9892); 1 sh, Leadsman Shoal, Raggie Reef, -8–12 m, mixed algal and coral reef, 1–2 km N of Leven Point (NMSA E6814); 4 sh, off Richards bay, -50 m, fine quartzite, broken sh, ex C.S.I.R. Water Research (NMSA A6112); 1 sh, off Sodwana Bay, -50 m, shell grit, ex C.S.I.R. Water Research (NMSA A5087); 7 sh, off Kosi Bay, -50 m, shell grit, ex C.S.I.R., 1975 Water Research (NMSA A4963); 1 sh, off Durban Bluff, 10 km SE of Cooper Lighthouse, -210 m, cone dredge, ex C.S.I.R., 1974 (Ecor 5) (NMSA A2993); 26 sh, off Kosi Bay, -100 m, ex C.S.I.R. Water Research 1977 (NMSA A5898); 20 sh, off Sodwana Bay, -100 m, ex C.S.I.R., 1976. (NMSA A5553); 3 sh, off Kosi Bay, -50 m, shell grit, ex C.S.I.R. Water Research (NMSAA5964).

Doubtful: SOUTH AFRICA: Eastern Cape: 1 sh (juv), Mzamba, beachdrift, leg. R. Kilburn & D. Herbert 12–30.v.1986 (NMSA W9680); 3 sh, Mzamba, beachdrift, leg. R. Kilburn & D. Herbert 12–30.v.1986 (NMSA D3021); 1 sh, Mtentu R. mouth, iv.1982 (JPM 2414); KwaZulu-Natal: 1 sh (larval), Landers Reef, off Scottburgh Area, -45 m, SCUBA, iv.1988 (JPM); 2 sh (worn), T. O. Strand, 2 km N of Port Edward (NMSA E1664).

Additional material examined: RÉUNION: 10 lv and 3 sh, Cap La Houssaye, dived, -8–17 m, varied bottom (NMSA K5444); 46 lv and 25 sh, Cap La Houssaye, -6–12 m (NMSA); 2 sh, Cap de La Réunion (MP); 2 sh, Réunion Is. (MP); TANZANIA: Zanzibar: 33 sh, Uroa (MP); KENYA: 3 sh, Kilifi, lagoon inshore of coral reef, sand from base of coral outcrops, -4 m (NMSA K7997); SUDAN: Red Sea: 57 sh, Sanghaneb Reef, leg. M. Oliverio 6.ii.1998 (MP); 6 sh, leg. M. Oliverio 4.ii.1992 (MP); 23 sh (2 larval), Sha'ab Rumi, leg. M. Oliverio 4.ii.1992 (MP); EGYPT: Red Sea: 47 sh, Abu Rhamada, Hurghada, leg. Liverani xi.1991 (MP); 2 dd, Sinai, leg. I. Nofroni; JORDAN: 1 sh (juv), Aqaba, leg. Liverani iv.1993; MAURITIUS: 3 sh Pointe Radeau, S of Roches Noires, shell debris, near reef gap (NMSA K9511); 2 sh, Riambel Lagoon, beach drift (NMSA K9821); 8 sh, Gris Gris, debris on surf beach opposite reef-break (NMSA K9186); INDIA: 1 sh, Andaman Is. (MP); JAPAN: 3dd, Amami I. (MP); HAWAII: 5 sh, Pali Coast, Maui I. (MP); 1 lv and 2 sh, SE Mokapu Point, Oahu I. (MP); 1 sh, Lanai I. (MP); AUSTRALIA: Queensland: 31 dd, N of Green I., E of Cairns (MP).

Distribution: Indo-West Pacific; this species is very common on the eastern coast of South Africa (Fig. 15).

Remarks: South African specimens show no relevant differences with respect to the specimens found all over the Indo-West Pacific.

Etymology: Named after Linda Davis, collections manager for Mollusca at NMSA.

Description: Tube subcylindrical, flaring towards the aperture. Aperture oblique, contracted, ending with three concentric rings. Septum protruding, with a strong, pointed mucro with subtriangular outline, slightly displaced toward the right side. Ventral side of the septum convex, dorsal one slightly concave. Early stages and operculum unknown.

Length: 2.5 mm.

Type locality: SOUTH AFRICA: Eastern Cape: Agulhas Bank, off Cape Morgan Lighthouse, -100 m.

Holotype (Fig. 25K): SOUTH AFRICA: Eastern Cape: dd, Agulhas Bank, off Cape Morgan Lighthouse, -100 m, depth broken coral + shell from (NMSA W9682/T3924), length 2.5 mm, min. diam. (posterior end) 0.39 mm, diam. in the middle of the tube 0.5 mm, max. diam. (apertural end) 0.56 mm.

Distribution: Currently known only front the type locality, Cape Morgan, north of East London (Fig. 15).

Remarks: Caecum lindae sp. n. shows aunique shape of the septum among South African species. It can only be compared with C. geigeri Pizzini & Raines, 2011, described from Austral Is., due to the similar shape of the septum, but it can be distinguished by the different shape of the tube and by the absence of the strong annulations preceding the aperture.

Material examined: SOUTH AFRICA: KwaZulu-Natal: 1 lv. Aliwal Shoal, off Umkomaas area, 27 m, SCUBA, i.1988 (JPM).

Comparative material examined: Caecum oahuense, lectotype (ANSP 127978) selected by Pizzini & Raines (2011: 29, fig. 2I).

Distribution: Caecum oahuense is found in the eastern Pacific Ocean (Pizzini & Raines 2011). A single specimen tentatively attributed to this species was found on the eastern South African coast (Fig. 15). The occurrence of Caecum oahuense in South Africa needs confirmation.

Remarks: This single specimen differs somewhat from C. oahuense by the more slender tube and finer sculpture.

Caecum neocaledonicum de Folin 1868, 57, pl. 6, figs 1, 2.

Caecum fulvum Kisch, 1959: 17–19, fig. 1.

Elephantanellum sp. A: Ladd 1972: 23, pl. 5, fig. 15.

Caecum hinoidei Habe, 1978: 4, figs 11–13.

Caecum (Brochina) sp. cf. glabella: Kay 1979: 111, fig. 42G.

Caecum neocaledonicum: Pizzini 1998: 33, figs 5–16.

Caecum neocaledonicum: Pizzini et al. 2013: 13, 15, figs 9G, H, J, K, 19H, 21A, B.

Type locality: NEW CALEDONIA.

Type material examined: Lectotype (MNHN-IM-2000-24909) selected by Pizzini (1998: 34, fig. 5).

Material examined: SOUTH AFRICA: KwaZulu-Natal: 1 sh (juv), between Bhanga Neck and Kosi Bay, reef off marker 13 north, -8 m, underwater pump (NMSA S2687); MAURITIUS: 20 sh, I. Pointe Radeau, S of Roches Noires, shell debris, near reef gap (NMSA K9538); 3 sh, Pointe Radeau, S of Roches Noires, shell debris, near reef gap (NMSA K9549); 1 sh, Grande Baie, SW side, beachdrift (NMSA K8864); 40 sh, Riambel Lagoon, beachdrift (NMSA K9796); 14 lv and 2 sh, Ilot Fourneau, lagoon, in clumps of fine green alga, <-1 m at L.S.T. (NMSA K9346); SEYCHELLES: 17 sh, E coast of Mahé I., -1 m (MP); 1 sh, Seychelles I., (MP); TANZANIA: 2 sh, Zanzibar, loc. Uroa, -25–30 m (MP); SOMALIA: 13 sh, Gesira (Yazirah) from beached material found in a little bay, (S. Palazzi colln, Modena, Italy).

Distribution: Indo-West Pacific. The occurrence of this species in South Africa is limited to a single juvenile specimen found close to the border with Mozambique (Fig. 17).

Caecum succineum de Folin, 1880: 810, 811.

Caecum succineum: de Folin 1881: 25, pl. 2, figs 12, 13.

Caecum succineum: de Folin 1886: 685, 686, pl. 3, figs 15, 16.

Caecum sp. a: Bosch et al. 1995: 49, n. 144.

Caecum succineum: Pizzini et al. 2013: 25, 26, figs 11Q, R, 12A–C, 191.

Type locality: St. 186, Flinders Passage, Cape York, 7 fms.

Type material examined: Lectotype (NHMUK 1887.2.9.2344) selected by Pizzini et al. (2013: 25, fig. 11R).

Material examined: SOUTH AFRICA: KwaZulu-Natal: 1 lv, between Bhanga Nek and Kosi Bay, reef off marker 13 north, -9–14 m (NMSA S1586); 1 lv (operculum in a small glass vial), Kosi Bay, main reef, 1–4 km S of estuary mouth, -18 m, underwater pump (NMSA S2303): 1 sh, Aliwal Shoal, off Scottburgh, -10 m, sand and reef debris, hand-dredged D. Herbert 4.iv.1992 (NMSA W9684).

Distribution: Indo-West Pacific; in South Africa this species was collected from the eastern coast (Fig. 17).

Remarks: This species is characterized by the presence of some rings in the abapical portion of the tube and by a low dome-shaped septum without mucro.

Caecum glabrum: Sowerby III 1892: 38.

Caecum glabratum: Bartsch 1915: 117.

Caecum glabrum: Turton 1932: 126.

Material examined: SOUTH AFRICA: Western Cape: 4 sh (1 broken), Knysna, Gericke Point, Sedgefield (NMSA W9658); Eastern Cape: 1 sh, Port Alfred, (J. Hutt colln, ex Albany Museum, 1980) (NMSA W9657).

Comparative material examined: C. glabrum: SWEDEN: 3 sh (2 broken), Persgrund, Koster Area, Bohuslän, 20–40 m, sand/clay, rectangular dredge, leg. C. Schänder vii.1994 (MP); U.K.: 8 sh (4 broken), Wales, Plymouth, Duke Rock, -8–10 m, leg. M. Thollesson & L. Gustavsson iv.1994 (MP); FRANCE: 13 sh, St. Malo, -15 m, leg. W. Segers 1978 (MP); 50 sh, Morbihan near Quiberon I., Penthièvre, Sauvage Coast, leg. Ron Voskuil 25.vii.1990 (MP); SPAIN: 3 sh, Laredo, viii.1992 (MP); MOROCCO: 3 sh, Rabat (MP); MAURITANIA: 2 sh, Banc d'Arguin, leg. E. Rolán (MP); SENEGAL: 1 sh, Gouye Teni M'Both, -25 m, sandy bottom clean and rocks, leg. J. Pelorce (MP); 1 sh, Grand Thiouriba, 40 m, sandy bottom clean and very large rocks, leg. J. Pelorce (MP); 4 sh, Cape Verde, shelly sand by diver, leg. Pelorce ix.1995 (MP); West Sahara: 10 sh, leg. J. Pelorce (MP); Cape Verde: 10 sh (1 larval), Ilha de São Vicente, Porto Mindelo, leg. J. Pelorce (MP); 1 sh, Ilha de Sal, Mordeira, -5 m, leg. J. Pelorce (MP); 1 lv, Ilha da Boa Vista, Sal Rei, Baixona, Derrabado, Rife de Chaves, Baia Teodora, Porto Ferreiro, -3 m, leg. J. Pelorce (MP).

Distribution: C. glabrum is known from the Atlantic coasts of Europe and western Africa up to Senegal. Specimens tentatively attributed to this species were found on the southern coast of South Africa (Fig. 17). Further study is required to ascertain their identity.

Remarks: Caecum glabrum is a well-known species described from English coasts and occurs along the Atlantic European coasts from Norway to Spain, and western African coasts from Morocco to Senegal, although it seems absent from Canary Is. (Aartsen 1977; Fretter & Graham 1978; Nofroni et al. 1997; van der Linden & Moolenbeek 2000; unpublished data). Additionally, it was reported for the Italian Miocene (Moroni & Ruggieri 1985). However, it is unclear whether Montagu's species coincides with C. glabrum as commonly intended, since the type could not be found in the NHMUK (K. Way, pers. comm.). Sowerby II (1859, pl. XV, fig. 7) illustrates C. glabrum from English coasts with the comment “rare and smooth”. Some years later (1892) Sowerby III reports this species from South Africa at Port Elizabeth; Bartsch (1915) cites this species al Port Alfred under the name C. glabratum. Conversely, Turton (1932) reports this species as common at Port Alfred. We found only a few specimens in the rich material stored in the NMSA.

South African specimens fit well with C. glabrum as commonly intended and only minor differences can be accounted for, such as a shorter and proportionally wider tube, a more pronounced swelling at the aperture and a duller surface. Notwithstanding these minor differences, the identification of South African specimens as C. glabrum is problematic. In fact, both present and historical records of this species in South Africa, ignoring possible misidentifications, come from the central and eastern part of the southern coast of South Africa, and there is no information about its occurrence either in the western part of the southern coast or along the western coast of Africa from Guinea to western South Africa.

With the present knowledge coming from studies on other groups, it seems unlikely to find species with a continuous distribution going from western Africa to southern South Africa. Among other well-studied molluscan families, there are only a few species with a western African or European to southern South African distribution, e.g. Talochlamys multistriata (Poli, 1795) among Pectinidae, which nevertheless shows a gap in Namibia (Dijkstra & Kilburn 2001). Furthermore, the pattern of southeastern Atlantic currents, with a northward-flowing Benguela Current and a southward-flowing Angola Current, which meet at around the Angolan-Namibian border, strongly suggests that western African and South African species are unrelated. However, the identity of European and South African populations cannot be ruled out, as it has been genetically demonstrated with a species of spider crab from the Lusitan area and South Africa (Sotelo et al. 2009).

For the time being, in the absence of a detailed study of European C. glabrum and more information coming from South African populations, we ascribe South African specimens to the European species by comparison only.

Type species: Moreletia cornucopiae de Folin, 1869 (by original designation, Folin 1869: 174) from Pacific Ocean.

Etymology: Derived from the Latin adjective ornatus (= adorned), referring to the longitudinal microsculpture that adorns the teleoconch.

Description: Tube bisinuous, semitransparent, vitreous. Coiled protoconch formed by about 1.1 whorls; uncoiled protoconch conical, about 0.5 mm long, ending in a clear varix. The varix is asymmetrical, flange-like in the adapical side, shaped into a ring in the abapical side. Teleoconch smooth, with only some growth lines, especially close to the aperture, defining irregular rings. Microsculpture composed by fine longitudinal threads, slightly dextrally wound around the tube, rather sparse adapically, finer and denser abapically. The threads are interrupted by the growth lines, producing a wavy appearance. Operculum unknown.

Length: 2.5–2.7 mm.

Type locality: SOUTH AFRICA: Eastern Cape: Mzamba.

Holotype (Fig. 25B): SOUTH AFRICA: Eastern Cape: sh, Mzamba, near KwaZulu-Natal border, vii.1976 (W9677/T3379), length 2.71 mm, protoconch diam.0.14 mm, max. diam. (apertural end) 0.46 mm.

Paratypes: SOUTH AFRICA: Eastern Cape: 1 sh, same data as holotype (JPM2119); 1 sh (broken), Mzamba, beach, leg. J.P. Marais vii.1976 (NMSA W9678/T3380).

Additional material examined: SOUTH AFRICA: KwaZulu-Natal: 2 sh, off Richards bay, shallow dredgings, viii.1986 (JPM) (lost).

Distribution: Eastern coast of South Africa (Fig. 20).

Remarks: This species can be compared with the Australian Parastrophia cygnicollis (Hedley, 1904) and P. erseusi Hughes, 1993. It differs from the former by the different shape of the tube, which is longer and more slender in P. cygnicollis, by the shape of the adapical side of the varix, smoothly flaring in cygnicollis, flange-like in ornata, and by the presence of a microsculpture composed of fine longitudinal threads, whereas in cygnicollis a microsculpture composed of a few longitudinal wavy grooves is sometimes visible (Pizzini et al. 2013: fig. 160). Conversely, Parastrophia erseusi differs by the more or less symmetrical, evenly rounded varix and by the absence of microsculpture (Hughes 1993). Parastrophia ornata sp. n. is also similar to P. melanesiana Pizzini, Raines & Vannozzi, 2013, which shares a similar microsculpture, but differs from it by the paucispiral coiled protoconch and by the different shape of the separation varix.

Etymology: The name is composed by the Greek α (not) and the Latin adjective varicosus (= provided with a varix) due to the absence of the varix between the uncoiled protoconch and the teleoconch that occurs in all the other Parastrophia species.

Description: Tube slightly bisinuous, very thin, vitreous, tapered. Coiled protoconch small, ovoid, of half a whorl. Uncoiled protoconch smooth, conical in the adapical half, then subcylindrical, curved and with a slight constriction before the transition to the teleoconch, which is marked by a simple scar. Teleoconch gently curved and slowly growing, characterized by the presence of a microsculpture composed by shallow, irregularly set grooves spaced about 5 µm apart. Aperture rounded, simple, without any feature. Length 1.5 mm. Operculum unknown.

Type locality: SOUTH AFRICA: Eastern Cape: Mzamba.

Holotype (Figs 19A–C, 25A): SOUTH AFRICA: Eastern Cape: sh, Mzamba, beach, leg. J.P. Marais vii. 1976 (NMSA E1665/T3354), length 1.47 mm, protoconch diam. 0.08 mm, max. diam. (apertural end) 0.26 mm.

Paratypes: MADAGASCAR: 9 sh, E of Cap Antsirabe, 25°02.8–03.0′S 47°01.3–02.0′E, sable vaso-sableux compact, -49–52 m, 6.v.2010 (MNHN-IM-2012-2726); 1 sh, Phare Flacourt, 25°01.3′S, 47°00.5′E, fond rocheux avec dalle, -18 m, 1.v.2010(MNHN-IM-2012-2727); 1 sh, SW of CapAndavaka, chalutier “NosyBe II”, -53–54 m, 25°16.9′S, 46°31.3′K, 4.v.2010 (MNHN-IM-2012-2728).

Comparative material examined: P. cornucopiae de Folin, 1869, lectotype (MNHN-IM-2000-24917) selected by Pizzini et al. 2013 (2013: 43, fig. 16F, G); P. filum Melvill, 1906, holotype from Gulf of Oman, 156 fms (NHMUK 190610.23.47); P. japonica Hinoide & Habe, 1978, holotype (NSMT-Mo 55474); P. melanesiana Pizzini, Raines & Vannozzi, 2013, holotype (MNHN-IM-2000-24882).

Distribution: This species is known only from the eastern coast of South Africa (type locality, Fig. 20) and from the southern coast of Madagascar around Talanaro.

Remarks: Parastrophia avaricosa sp. n. is the only known Parastrophia species without a separation varix between protoconch and teleoconch, thus it is immediately distinguished from all the other congeners. The new species resembles P. cornucopiae de Folin, 1869, P. japonica Hinoide & Habe, 1978 and P. melanesiana Pizzini, Raines & Vannozzi, 2013 (all figured in Pizzini et al. 2013) due to the paucispiral protoconch. Parastrophia cornucopiae is similar to P. avaricosa, having in common a similar shape of the protoconch, but the latter completely lacks the varix separating the uncoiled protoconch from teleoconch. Moreover, Parastrophia avaricosa shows a microsculpture composed by fine collabral grooves that is not observed in P. cornucopiae. Parastrophia avaricosa is also similar to P. japonica and P. melanesiana, but the latter two show a distinct separation varix and a longitudinal microsculpture (Pizzini et al. 2013).