166 MOLLUSOA FROM THE CRAG. 



Cemoria,* Leach, 1819. 



Diadora. Gray, 1821. 

 Sypho. Brown, 1827. 

 Punctukella. Lowe, 1828. 

 Rimula. Loven, 1846. 

 Fissurella (spec.) Flem. 

 Patella (spec.) Mull. 



Gen. Char. Shell small, patelliform, like an Eniarginula, 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 

 Fissurella, 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 genus. 



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



Patella noachina. Linn. Mantissa, p. 551. 



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

 Fissurella noachina. Lyett. Obs. upon the Elev. of Sweden. 

 Puncturella noachina. Lowe. Zool. Journ. vol. hi, p. 77, 1828. 

 Sypho striata. Brown. Illust. Brit. Conch, pi. 36, fig. 14-16, 1827. 

 Cemoria Flemingii. Leach. MS. 1819. 



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



C. Testa conicd, crassd, costatd, costis rugosis, confertis, inoeaualibus, radiantibus ; 

 vertice vix iniorto ; basi ovatd ; margine crenulatd. 



Shell strong, conical, and costated, with numerous rugose rays or costas, 

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

 deep muscular impression. 



Longest diameter of base, f ; altitude, f of an inch. 



Locality. Mam. Crag, Bridlington. 



Recent, Arctic Seas, and Seas of Boreal America. 



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

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

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



* Etym. (?) 



