GASTROPODA 
OF THE 
OCRETACKEOUS ROCKS OF SOUTHERN INDIA. 
Sub-kingdom, MOLLUSCA. 
Class, GASTROPODA, Cuwwier. 
CHARACTERS.—Vollusca, with a more or less distinct head, being generally pro- 
vided with tentacles,* a muscular foot developed for digging, swimming, fastening on 
submarine objects, creeping, or rudimentary,t with or without other locomotive 
appendages of different shape; mantle open usually in front and below, more rarely 
on both ends,t or even wanting ; shell, if present, either univalve or multivalve,§ with 
or without an operculum, which is not exactly equivalent to the second valve of the 
Pelecypoda or Elatobranchia; genital organs placed usually unsymmetrically, seldom 
symmetrically,|| or in pairs,¥ but always opening on one side only. 
We have previously noticed, that it appears convenient to divide the entire 
class of Gastropoda into eight orders; namely, Scaphopoda, Pteropoda, Opistho- 
branchia, Chitonide (Polyplacophora, Blv.), Heteropoda, Prosobranchia, Newrobran- 
chia and Pulmonata. The cretaceous rocks of Southern India have not as yet 
yielded remains of all these orders, and there is, therefore, no inducement for us 
to notice those, which are absent, any farther in detail. For sufficient information 
as to all the orders and other sub-divisions, we would specially refer the reader 
to the description in Bronn’s “ Klassen und Ordnungen des Thierreiches,” Vol. IIT 
(continued by Dr. Keferstein). 
The remains of Gastropoda, which we are about to describe more fully here, 
belong to the four divisions, the Scaphopoda, Opisthobranchia, Prosobranchia and 
Pulmonata, and we shall confine our remarks to what may be necessary to the 
understanding of these four divisions, so far as regards the special purposes of our 
present description and the geological importance of the groups. 
* To these Bronn’s name Pselaphocephala refers, but as they are wanting in almost a greater number of 
species, than is the foot, the name is not more characteristic. The tentacles are wanting in a few genera of 
the Heteropoda, Opisthobranchia, Pteropoda, and in all Chitonide. 
+ The foot is wanting in one or two Pteropoda and three or four other genera of the Gastropoda even as 
a rudiment. { In the Dentalide. § Chitonide. || Dentalide. © Chitonide. 
B 
