8 



Records of the Indian Museum. [Vol. XXII, 



is never prominent and the surface of the shell always has a 

 smooth appearance. The periostracum is of some olivaceous tint, 

 often with dark spiral bands. The interior of the shell is pale but 

 still more frequently with dark spiral bands. 



The operculum is thick and testaceous with an outer horny 

 layer, more or less fJame-shaped in outline. It exhibits no trace 

 of spiral sculpture, but bears on the internal surface a large elongate 

 sculptured scar. Its nacre is polished but not iridescent. 



Fig. I.- Radular teeth of Ampullar 



A. Pacliylabra globosa. 



B. Pachylabra nevilliana. 



C. Turbinicola mix. 



The radula. — Ovj'm^ to the poor figures published by Troschel ' 

 and Fischer ^ great confusion has been caused as to the exact struc- 

 ture of the radular teeth of Pachylabra. One of us has recently 

 (loc. cit.) figured the radular teeth of some of the vSiamese species. 

 We now figure those of P. globosa, the type-species of the genus. 

 Without giving a detailed description we may note that the 

 marginal teeth have three denticulations, of these the middle one 

 is the largest and best developed and is always sharply pointed, 



' Troschel, Gebiss der Schnecken, I, p. 

 S Fischer, Jltan. Conchyliol. p. 7,^6, fig. 



3, pi. vi, fig. 

 :o5(i887). 



5 (1856-1863). 



