Prof. E. Forbes on Fossil Invertebrata from Southern India. 151 



the last. The outline is also very different. They are however nearly allied, and, 

 with the next, belong to a group of Trigonire (T. ajinis and T. excentrica are ex- 

 amples) which in Europe are characteristic of the lower part of the Cretaceous 

 system. 



Locality, Pondicherry. 



3. Trigonia semiculta, sp. nov. PI. XVIII. fig. 9. 



T. testa oblique obovata, depress^, subrostrata, tertia parte profunde regulariter transverse 

 sulcata, reliqua testa Isevigata. 



Length Iji inch. Breadth 2^^ inches. 



Depressed, obovate, broadly beaked ; the beaked end smooth, the remainder of 

 the shell for about two-thirds of its surface transversely sulcatedby more than sixty 

 shallow furrows. Near the beak the entire shell is sulcated across ; so also is the 

 young shell. The nearest relative of this species is the Trigonia affinis of the 

 upper greensand. 



Locality, Verdachellum. 



4. Trigonia aliformis, Parkinson. PI. XIV. fig. 3. 



There are small, but well-preserved specimens of this species in the Verda- 

 chellum collection, which cannot be distinguished from British examples. 



Genus Avicula, Brugui^re. 



1. Avicula nitida, sp. nov. PI. XVI. fig. 6. 



A. testa laevi, tumida, oblique trigone, antice dilatata, compress^, postice acute rostrata, basi 

 rostri abrupta, urabonibus prominentibus, margine dorsali recto. 



Oblique measurement from beak to foremost part of margin 1^ inch. Dorsal line 1^ inch. 

 Thickness of united valves Ol| inch. 



A smooth, shining species, broadly triangular and considerably produced on the 

 short side. It is a very distinct and rather peculiar form. 

 Locality, Pondicherry. 



Genus Mytilus, Linnaeus. 

 [Section A. Mytilus auctorum.] 

 1. Mytilus nitens, sp. nov. PI. XVI. fig. 8. 



M. testa laevigata, transverse obscure sulcatA, ovato-lanceolatA, line^ cardinal! recta, postice 

 sinuata, antice rotundata, umbonibus prominentibus. 



Oblique distance from beak to furthest margin Oy'g inch. Line of hinge Oy^g inch. Thick- 

 ness of united valves 0-^^ inch. 



x2 



