166 MOLLUSCA FROM THE CRAG. 



Cemoria,* Leach, 1819. 



DiADOKA. Gray, 1821. 

 Sypho. Brown, 1827. 

 PuNCTUEELLA. Lowe, 1828. 

 RiMULA. Loven, 1846. 

 FissuKELLA (spec.) Fle7n. 

 Patella (spec.) Mull. 



Ge?i. Char. Shell small, patelliform, like an Emarginula, with an ovate base, and 

 entire margin ; apex elevated, slightly recurved ; a perforation in the upper part of the 

 shell before the vertex, and a thickened plate within, above the fissure. 



But one species of this genus is as yet known, and this has been placed with FissureUa, 

 from which, however, it is now determined to be perfectly distinct. It much resembles 

 the genus Rimula, in having its opening between the margin and the vertex, and 

 rather nearer to the latter ; but a recent species of the genus Rimula, in the British 

 Museum, shown me by J. E. Gray, Esq., has a fissure in the centre of the shell, without 

 the internal thickened plate of the present genus ; but until more information is 

 obtained respecting the animal inhabitant, this may be considered as a distinct 



1. Cemoria noachina. Lirm. Tab. XVIII, fig. 5, a — c. 



Patella noachina. Linn. Mantissa, p. 551. 



— FISSUKELLA. Mull. Zool. Dan. i, t. 24, fig. 4-6. 

 Fissurella noachina. Lyell. Obs. upoii the Elev. of Sweden. 

 PuNCTURELLA NOACHINA. Loive. Zool. Joum. vol. iii, p. 77, 1828. 

 Sypho striata. Brown. lUust. Brit. Conch, pi. 36, fig. 14-lC, 1827. 

 Cemoria Flemjngii. Leach. MS. 1819. 



— NOACHINA. Gould. Inv. of Massachus. p. 156, fig. 18, 1841. 



C. Testa conicd, crassd, costatd, costis nigosls, confertis, incequalibiis, radiantihm ; 

 vertice vix intorto ; basi ovatd ; marline crenulatd. 



Shell strong, conical, and costated, with numerous rugose rays or costag, generally 

 alternating large and small, with the fissure of a triangular shape, and a deep muscular 

 impression. 



Longest diameter of base, | ; altitude, % of an inch. 



Locality. Mam. Crag, Bridlington. 



Recent, Arctic Seas, and Seas of Boreal America. 



This is at present knowTi as a Crag fossil only from the above locality. The 

 specimen figured is from the cabinet of Mr. Leckenby. One sijccimen, also, is among 

 the shells sent by Mr. Bean. There is, I conceive, but little doubt of its identity with 



* Etym. (?) 



