Perfil taxonómico: Crustipellis (Harman & Loden 1978)

The taxon Opistocysta flagellum (Leidy, 1880) has long been considered a species inquirenda. Harman (1970 [1969 sic]) first made this determination because Leidy's (1880) description of this taxon was inadequate [incomplete]; searching for the type material had been unsuccessful, and collections from the type locality have not yielded specimens for study that could be attributed to this taxon as originally described. The following year (in Brinkhurst and Jamieson, 1971: 642-643), this determination was reiterated: 'Both W.J. Harman and the author [R.O. Brinkhurst] have sought the type specimens in vain, and a search of the type locality has failed to yield fresh material. In view of the diversity of characters displayed by S. American material and material from the southern states of the U.S.A., it is no longer possible to accept this as a valid species. I [Brinkhurst] agree with Harman (1970 [1969 sic]) that the best course of action is to remove this contentious name from consideration in the current nomenclature of the family'... Harman and Loden (1978) re-evaluated the family, discussing further the problems in verifying the validity of historical records published in the literature, at the same time erecting two new genera in this family, Trieminentia and Crustipellis into which the former Opistocysta tribranchiata and Opistocysta corderi, respectively, were transferred as their type species; one must read the cited papers for this account to fully understand the nomenclatural and systematic history of the genus Opistocysta, and the family Opistocystidae