Prof. E. Forbes on Fossil Invertehrata from Southern India. 153 



5. Mytilus (Modiolus) pulcher, sp. nov. PL XIV. fig. 6, 



M. testa tumida, valde inaequilaterali, tetragona, oblique carinata, carina dia"-onali, obtusa, 

 longitudinaliter transverseque striis minutis regularibus ornata ; margine dorsali compresso, 

 frontali subsinuato, umbonibus recurvis gibbosis (nucleo la;vi, polito). 



Beak to anterior angle Ij^ inch. Greatest breadth l^'^ inch. Greatest thickness 0^-'^ inch. 

 Hinge-line Oy^^^ inch or a little more. 



A very curious and beautiful form, which at first sight so closely resembles a 

 Cypricardia or a Myaconcha that its relationship to Mytilus seems obscure. On 

 close examination however, the hinge appears to be that of a Mytilus, and making 

 allowances for exaggerations of parts, the general form does not really depart very 

 far from that of some existing species of the section Modiolus. The fine striae 

 obliquely crossing each other on the surface of the shell confirm the relationship. 

 When the shell is held up with its back towards the observer, the outline of the 

 united valves appears nearly tetragonal. The cast is very smooth and highly 

 polished. 



Locality. It appears to be plentiful at Pondicherry, 



Genus Pinna, Linnaeus. 



1. Pinna arata, sp. nov. PL XVI. fig. 10. 



P. testa lanceolata, compressa, undique longitudinaliter regulariterque sulcata. 

 At 2i inches from the beak this Pinna measures 0|f ths of an inch broad. The fragment is 

 3 inches long. It appears to be distinct from any described or figured fossil form. 



Locality, Pondicherry. 



2. Pinna restituta, Hoeninghaus. 



Fragments of considerable size from Pondicherry, undistinguishable from this 

 greensand species. 



3. Pinna decussata, Goldfuss. 



Fragments of a fine Pinna occur in the Verdachellum collection, which appear 

 to be identical with the species so named from the cretaceous strata of Westphalia. 



Genus Pecten, Brugui^re. 



1. Pecten quinquecostatus, Sowerby. 



Of this very characteristic cretaceous species there are specimens in the collec- 

 tion, from both Pondicherry and Verdachellum, which cannot be distinguished from 

 specimens from the greensand of Blackdown. 



