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



most important source of character among the Venerida — was well-marked and 

 characteristic. A greensand shell from Germany, the "■ Lucina ienticularis" of 

 Goldfuss, is very similar in outline to the Indian fossil. 

 Locality, Verdachellum. 



Genus Nucula, Lamarck. 



1. A single species of this genus, as now restricted, is contained in the Pondi- 

 cherry collection. It is a smooth, polished, transversely ovate shell, very inequi- 

 lateral, angulated behind and rounded before ; the margins are smooth ; these 

 characters would almost apply to many Nucula, recent and fossil, for the varia- 

 tions of form in this genus have been as slight and unsatisfactory in time as they 

 are now in space. It may provisionally be named Nucula indefinita ; though diffi- 

 cult to define, I have little doubt that when well-preserved specimens shall have 

 been procured it will prove very distinct. 



Genus Led a, Schumacher. 

 1. Leda striatula, sp. nov. PI. XVII. fig. 14. 



L. testa transverse oblonga, compressa, subaequilaterali, striis subobliquis ornata, postice 

 late sed brevirostrata, subangulata, antice rotundata. 



Length 0/^ inch. Breadth 0-^ inch. Thickness of united valves 0^^ inch. 



A very distinct and well-marked species, remarkable for its compression, broad 

 beak, and surface ornamented with very fine, numerous oblique striae. It is allied 

 most nearly to the Nucula scapha of D'Orbigny, a lower greensand species found 

 in both France and England. 



Locality, Pondicherry. 



Genus Arca, Linnseus. 



1. Arcajapetica, sp. nov. PI. XVI. fig. 2. 



A. testa inflata, carinata, transverse ovata, antice oblique truncata, postice angustata, lateribus 

 striatis, in medio sulcato-striata, margine frontali recto ; area cardinali lata, umbonibus pro- 

 minentibus distantibus. 



Extreme length 2i inches. Extreme breadth 2| inches. Thickness 2y'2 inches. Distance 

 between beaks Oy'^ inch. Area ly§ inch. 



A strong, inflated, carinated, longitudinally sulcated species with an extensive 

 cardinal area. It is allied to the Arca exaltata of Nilsson, a lower greensand species. 

 Locality, Pondicherry. 



2. Arca Gamana, sp. nov. PL XVI. fig. 3. 



A. testa inflata, carinata, transverse subquadrata, laevigata, anticfe obliqu^ truncata, angulata. 



