We have taken advantage of the size of the macrostomal oral apparatus of Tetrahymena vorax to investigate the immunofluorescent localization of three cytoskeletal proteins—tetrin, actin, and centrin. Tetrin and actin antibodies co-localize to cross-connectives that anchor the membranelles. These antibodies also recognize the coarse filamentous reticulum, a filament associated with the undulating membrane. Actin-specific localization extends beyond the coarse filamentous reticulum-undulating membrane complex into a region called the specialized cytoplasm. A centrin antibody localizes to the fine filamentous reticulum which, along with microtubules of the oral ribs, circumscribes the cytostomal opening. Models of phagocytic contraction based on these data are presented.