42 RESjiARCHES LPOX THE HYDROBIINiE 



a denticle, at the outer side of the single basal denticle. Inter- 

 mediate tooth with the body quadrate and strongly projecting at 

 its infero-interior angle, which is blunt ; peduncle very long. 

 Formula of the denticles : ^— ^ - 5 - 12 - 12. 



Station, brackish or sea^-water in sheltered positions. 



Distribution, probably mundane. 



Type L. ventrosa. — Turbo ventrosus, Moxt. — Cyclostoma acutum, Drap. — 

 Rissoa ventrosa, Forbes & Hanl., Brit. Moll., Ill, (1853,) 138, Ixxxvii, 1, 5, 

 6, 7. Hub. Europe. 



The following species belongs, with little doubt, to the same 

 genus : — 



L. minitfa. — Turbo minutus, Totten. — Cingula minuta, Gould, Inv. Mass. 

 (1841,) 265, fig. 171. New England 



The name Littorinella was originally proposed by Braun for 

 " the Paludinas with a spiral operculum," which would make it 

 include nearly the entire subfamily ; and no species are mentioned 

 by him, from which we can select a type. Thomoe, in the " Jahr- 

 buch,"ciuoted above, was the next author who used the name, and 

 his first species must be taken as the type. This species is the 

 Cyclostoma acutum of Drapaniaud, a brackish-water or marine 

 species, identical with the Turbo ventrosus of Montagu. The 

 characters of the soft parts of this species, including its lingual 

 dentition, are as yet unknown, but the shell so closely resembles 

 that of the common "Cingula minuta" of the coast of New Eng- 

 land, that we can have little doubt that they are congeneric. The 

 characters of the animal, other than conchological ones, have there- 

 fore been drawn from the latter species. These characters seem to 

 forbid its generic association with Hydrohia as typified by H. idvse. 

 But, should the soft parts of Montagu's Tur-bo ventrosus be found, 

 upon examination, to present characters diflfering generically from 

 those of Totten's Turbo mitiutus, or if they do not so differ should 

 Thomse's shell be found to be generically distinct from the Turbo 

 ventrosus, we would propose for the genus here indicated, the name 

 Ecrobia, with Turbo minutus as tlie type. In our efforts to retain 

 the names previously applied without knowledge of the true charac- 

 ters, to members of the group under consideration, and to avoid the 

 introduction of new names which may prove to be synonyms, we 

 experience great difficulty in ascertaining the typical species upon 

 which such genera must be supposed to be founded ; and when 



