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



may as well be united, and it will be seen that among the following species we 

 have some which assuredly commence life in the form on which M. D'Orbigny 

 has founded his genus Helicoceras. 



1. Hamites subcompressus, sp. nov. PI. XI. fig. 6. 



H. testa elongata, compressa, crebricostata, costis subdistantibus, continuis, simplicibus, 

 obtusis, regularibus, sulcis oralibus interruptis. 



Circumference of largest specimen, ly'^ inch. 



Shell presenting an elliptical section, compressed at the sides, ornamented with 

 encircling ribs which are very regular, and separated by shallow furrows, each of 

 which is about three times the breadth of a rib. At intervals they are interrupted 

 by deep and broad sulcations, indicating stages of growth. The sutures show that 

 the chambers were of no great dimensions, though separated by complicated par- 

 titions. Both lobes and saddles are bifurcated and even. The pinnations of the 

 lobes are not deep, hence their margins are but slightly denticulated and the inter- 

 spaces broad. 



Locality, Pondicherry. 



2. Hamites tenuisulcatus, sp. nov. PI. XL fig. 3. 



H. testa elongata, rotundata, crebricostata ; costis numerosissimis, fillformibus, continuis, 

 obliquis, regularibus, simplicibus. 



Circumference of largest specimen, 2j\j inches. 



Shell ornamented with very fine and closely-ranged thread-like ribs, which run 

 obliquely though regularly, and are slightly rounded at their summits. In some of 

 the specimens they are interrupted at distant intervals by varices and furrows, indi- 

 cating arrests of growth. The interstices are narrow, shallow and smooth. All the 

 specimens are more or less curved, some very slightly, others suddenly. The pos- 

 terior extremity terminates in an obliquely-coiled helicoid spire. The sutures of 

 the chambers are well seen in one of the most curved examples. From it we know 

 the chambers to have been distant, and the partitions divided into evenly furcated 

 lobes and saddles. The largest saddle is the superior lateral ; the pinnations of the 

 lobes are not deep, but the larger divisions are wide-spreading. On the whole, the 

 sutures are more complex than in the last species. 



Locality, Pondicherry : frequent. 



3. Hamites indicus, sp. nov. PL XI. fig. 4. 



H. testa elongata, rotundata seu subcompressa, crebricostata ; costis continuis, regularibus, 

 simplicibus, subacutis, approximatis (nucleo obtusis). 

 Circumference of largest specimen, 2 inches. 



This Hamite differs from large-sulcatus in having much more frequent ribs, 



