rOROMYA. 203 



Mr. M' Andrew had previously procured some examples, 

 dredging them at the depth of forty fathoms. In the 

 -^gean, where it was first met with, dead valves are 

 frequent in mud, taken between the great depths of 80 to 

 200 fathoms. It is now known also as an inhabitant of 

 the Norwegian seas. The Neczra tenuis of Hinds is nearly 

 allied to this species. 



POROMYA, Forbes. 



Shell ovate or suborbicular, equivalve, inequilateral, 

 slightly produced posteriorly ; surface invested with a 

 scabrous epidermis, beneath which it is pearly and mi- 

 nutely punctated ; hinge of a minute cardinal ossicle or 

 erect tooth in one valve lodged in a pit or rather 

 impression in the other ; no lateral teeth ; ligament exter- 

 nal ; pallia! impression very slightly sinuated. 



Animal unknown ; but probably closely resembling that 

 of Neeera. 



This genus was founded for the reception of a Mediter- 

 ranean shell which proved eventually to be identical witli 

 the tertiary fossil described by Nyst, under the name 

 of Corhula granulata. Subsequently, the beautiful shell 

 described by Mr. Hinds under the name of Neetra hyalina, 

 and now in the Cumingian cabinet, proved to be congeneric, 

 and afforded better opportunities than the fragmentary and 

 rare shell before mentioned, for an investigation of the 

 character of the hinge. Two remarkable cretaceous fossils 

 from Pondicherry, and a European species of the same age, 

 all presenting similar peculiarities of structure, were after- 

 wards associated with it,* and very recently a new living 



* Forbes on Fossils of Soutliern India. Geol. Trans. 2nd Ser. vol. vii. p. 140. 



