Prof, E, Forbes on Fossil Invertebrata from Southern India. 109 



umbilicum et juxta dorsum prominentibus, in dorso iuterruptis ; dorso rotundato, in medio 

 laevigato ; apertura ovato-trigona, angulis obtusis. 



Diameter 3| inches. 



Length of mouth 1| inch. 



Thickness at mouth li inch. 



Thickness at second whorl .... 1^ inch. 



A subcompressed shell of several rounded whorls, the outermost much the 

 largest, and ornamented with ribs which, rising strongly from the umbilicus, be- 

 come almost obsolete on the centre of the whorl, and reappear in the shape of 

 oblong tubercles on the region of the back ; these tubercles are however altogether 

 absent in the last chamber on the adult shell. The back itself is rounded and 

 smooth. The mouth is broadly ovate and subtrigonal. 



The chambers are rather complicated. There are three lateral lobes, the supe- 

 rior one largest and trifurcated, as are also the others, but in a less degree. The 

 superior lateral greatly exceeds the dorsal, which is short and two-branched, the 

 branches slender and spreading. The saddles are two-branched, the lateral one 

 being larger than the dorsal. 



Locality, Pondicherry. A form connecting such Ammonites as A. Renavxianus 

 and^. radiatus with the group of which A. Carteroni, A, fascicularis, and the Indian 

 A. Chrishna are examples. 



Dentati. 



19. Ammonites Cunliffei, sp, nov. PI. VIII. lig. 2. 



A. testa compressa, undulata ; dorso compresso, laevigato, lateraliter tuberculato, tuberculis 

 distantibus ; umbilico angusto, marginato, margine tuberculato ; apertur^ compressa, superne 

 truncata. 



Diameter 1^^^ inch. 



Diameter of outer whorl Oj^^ inch. 



Median thickness 0— inch. 



Shell laterally compressed, the back much depressed and bordered on each side 

 by a row of distant, very prominent tubercles, seven on each side of the outer 

 whorl. The foremost of these is at some distance from the mouth, and in front of 

 it the undulations on the shell are strongest and inclined to bifurcate. There is 

 another row of smaller and closer tubercles on the inner margin of the whorls, 

 which forms a steep and sudden wall round the narrow umbihcus. Consequently 

 the base of the mouth is broad, and the latter assumes an ovato-quadrate form. 



The lateral lobes of the chambers are three, much divided and spreading, and 

 more or less trifurcated. The dorsal lobe is oblong and not deeply divided, but 

 branched at its extremity into two short trifurcating arms. It is fully as long or 

 longer than the superior lateral. The saddles are more or less regularly bifur- 



VOL. VII. SECOND SERIES. Q 



