OE SOUTHERN INDIA. lil 



5. Venenipis, Lamarck, 1818. Shell sub-quadraugular, " more or less 

 laterally compressed, posteriorly often somewliat dilatated and gaping ; surface 

 radiately ribbed, and at least towards the posterior end laminar; liin"'e with 

 three usually distinct sub-equal teeth in each valve, the middle teeth generally 

 are the strongest and farrowed ; the anterior tooth of the right valve usually is 

 the smallest, but it very rarely becomes obsolete. Lamarck's 2)ow«a; m<s, Linn., 

 is the type of the genus. 



The hinge- teeth of Venerupis are very distinct from those of Bnpellaria as 

 restricted; they are sub-equal, close together and diverging, exactly similar to 

 those of Tapes. This form of the hiuge-teeth is observable even in those species 

 which are a little ventricose and resemble Bnpellaria in form. For this reason the 

 genus has been classed by H. and A. Adams in the tapesinje, but the general charac- 

 ter and ornamentation of the shell with the overlapping margins of the mantle 

 anteriorly, as distinctly indicated in some species, further, the rounded form of 

 the small foot and the habitat of the shells, sufficiently indicate their close 

 relation to Petricola. 



List of cretaceous species. 



Witli the exception of a single imperfect specimen, I am not acquainted with any species of 

 PeTRICOLID^ from the cretaceous rocks of Southern India, Ijut a few liave been described from other 

 countries. Pictet and Campiche (Pal. Suisse, 4-™" ser., p. 163, &c.,) quote the following : — 



1-4. — Petr. neocomiensii, Buv., Pet. lihodani, P. and R., and Pet. Meriani, P. and C. (both 

 probably belonging to CJioristodon) , Escheri, P. and C. 



Pelr. nuciformis and canaliculata of Sowerljy are justly excluded from this family altogether; 

 the former is a Corhis, or some allied genus, and the latter a Cavdium. 



5-7. — Venerupis neocomiensis, Buv., V. Landeroniana, P. and C, and T. Scuroneti, P. and C. 

 The two former are known only from cast specimens ; the first may be a Rupellaria ; and the last, 

 of which Pictet and Campiche only give a short characteristic, may also belong to the same genus. 



I do not know of any other species having been described since Pictet and Campiche's 

 publication, 1865. 



8. — Choristodon ? A single specimen occurred in the white limestone of Ninnyoor. It 

 has the general form of Choristodon, and traces of shell certainly indicate by their earthy and soft 

 structure a species of this genus. The shape is quadrangularly ovate and very tumid ; the surface 

 appears to have been finely striated concentrically, aud a deep ascending sinus is indicated, thougii 

 not distinctly; vide pi. xvii, fig. 3. 



XIV. Family —VENEBIBJE. 



The organisation of the animals belonging to the present family must be 

 regarded as characteristic of all the V EN Ell ACE A. As a rule, the animals have 

 an elongated or roundish oval shape, are moderately thick, have a thin mantle with 

 thick, sometimes crenated edges, united only for a very short distance below the 

 siphons. The gills are large, sub-angular, two on each side ; the palpi generally 

 small. The foot is stout, sometimes thick, sub-qiiadrangular, but usually prolonged, 

 pointed at the end, and below sometimes furnished with a byssal groove, the byssus 

 bemg, however, developed only in some of the compressed forms, like Tapes aud 



2 M 



