254 CRETACEOUS PELECYPODA 



tliem, but the only specimen we possess has not the surface in such a good state 

 as to show tliis sufficiently clearly. In the left valve the beak is curved anteriorly ; 

 mmediately below it there is a lamclliform tooth, and a second one a little in front 

 and below it ; one narrow ridge runs the whole length of the areal margin and 

 terminates with a small posterior tubercular tooth. 



Locality. — Olapaudy, in an oolitic brownish calcareous and earthy rock ; appa- 

 rently very rare. 



Formation . — Arrialoor group. 



? Sphcei'iola, sp. ind. 

 Only two imperfect cast specimens of a small, rounded, tumid, concentrically 

 lamellated species were met with in the light coloured Arrialoor sandstone near 

 Stripermatur, in company with EijJl^ac/m Aemilianus. One valve is 5 m. m. long, 

 4i m. m. high, and 2 m. m. thick. In external appearance the shell resembles 

 some of the Jurassic species of Sphceriola, but it is impossible to trace the hinge- 

 teeth. The discovery of better materials will, it is hoped, settle the determination 

 of this species. 



CORBIS, Cm., 1817, (see p. 248). 



1. CoKBis TYPiCA, Stoliczka, PI. XIII, Eigs. 11-12. 



C. testa siihquadrangidariter ovata, siibceqiulaterali, antice late rotimdata, pos- 

 tice angustata et oblique sub-truncata, umbonibus valde tumidis, latis, antice verms in- 

 curvis, approximatis ; Itmula parva, profunda, Icevigata ; margine areali stih-ecto, de- 

 clivi ; margine ventrali leviter curvato ; superficie costulis concentricis crassis confertis 

 antice ac post ice sulcis radiantibus deciissatis et in medio striis tennioribus radiantibus 

 ornata; cardine dentibus duohus cardinalibiis et lateraUbus instrncto, laterali antico 

 multo crassiori qiiam j^ostico, et cardmalibus approximato ; ligamento in excavatione 

 profunda sito ; margine interiori onmino crasse et pliciforme denticidato. 



Height of shell : its length ... ... ... ... 0-80 



Thickness „ : „ ... •■• ••■ •■■ 0-60 



This is a typical species of Corbis, in form and ornamentation resembling the 

 recent C. fimbriata, but higher and more attenuated posteriorly; the radiating 

 striation is at both ends much stronger than in the middle of the shell, where 

 it is only observable in the depressions separating the concentric ribs. 



We have received from the late L. Seem an of Paris a species under the name 

 of Corbis snbclathrata from the so-called Asphalt-beds (Kimmeridgien) of Hanover. 

 This species is very closely alHed to our cretaceous shell, it only appears to be a 

 little more flexuous posteriorly. 



Locality. — Ninnyoor, in a white earthy limestone ; apparently rare. 



Formation. — Arrialoor group. 



