Notes on Species of Corbiculadaz. 87 



vestita ; irregulariter striata ; valvis solidis, intus albis ; umbonibus 

 depressis, brevibus, sa3pius erosis ; cardine incrassato ; dentibus cardi- 

 nalibus brevibus, obliquis, fere parallelis, majoribus snperne canaliculars ; 

 lateralibus parvulis, compressis. 



Long. 59 ; lat. 51 ; diam. 30 mill. 



Sab. — Siam. Collect. Cuming et Prime. 



The shell is transversely rounded, subtrigonal, inequilateral, 

 and somewhat inflated. The lateral margins are more or less 

 abrupt, and more especially the posterior margin. The valves 

 are solid, and they are convex in the centre of the discs. The 

 epidermis is dark brown without polish. The stride are coarse 

 and irregular. The beaks are small and compressed, and are fre- 

 quently very much eroded. The interior is white. The hinge 

 is curved and not very broad ; the cardinal teeth are short, 

 subparallel, the two principal ones are bifid ; the lateral teeth 

 are nearly of the same length, they are short and not much 

 raised. 



Very closely allied to Cyrena Sumatrica, it is however less 

 inflated, less transverse, and the hinge is much more curved. 

 Compared with Cyrena ponderosa, it is less transverse and less 

 produced on the anterior side. 



4. Cyrema ponderosa, Prime. 



Cyrena ponderosa, Prime. Acad. N". S. Phil. 80. 1860. 

 Prime Cat. 6. 1863. 



C. testa transversa, subtrigona, inrequilaterali, subinflata ; latere antico 

 producto, postico subtruncato ; valvis solidis, intus candidis ; umbonibus 

 brevibus, obliquis, ssepius erosis ; irregulariter et dense striata ; epider- 

 mide brunnea induta ; cardine incrassato ; dentibus compressis, cardi- 

 nalibus fere parallelis. 



Long. 53 ; lat. 45 ; diam. 32 mill. 



Hab. — Insulae Philippinenses. Collect. Acad. Phil, et Prime. 



