376 CRETACEOUS PELECYPODA 



ab timbone ntriusqtie vahulce oblique ad mm^ginein ventralem decurrente, antice ct 

 postlce sulciilis marginata. 



Length of sb ell : height ... .., ... ... 1-50 



: thickness ... ... ... ... 1-33 



This is one of tlie very few species whicli by its short tumid form, concentric 

 strise of growth, and the broad incurved beaks, indicate the occurrence of the sub- 

 genus Botula in cretaceous deposits. The species is particularly characterized by 

 the sub-median depression fmde pi. xxxviii, fig. 13), which extends from the beak 

 of each valve to about the middle of the ventral portion. 



Localit]). — South-east of Arrialoor, in a conglomeratic whitish sandstone ; only 

 the figured specimen has been found. 



Formation. — Arrialoor group. 



2. LiTHODOMTJS ciJiiTA, StoUczJca, PI. XXIII, Pig. 17. 



Lilh,. testa ovato-cylindracea, antice ac postice sid)-truncata, umbonibus anticis, 

 parmdis, svperjicie co7icentriGe striata. 



Length of shell : height... ... ... ... ... 1'8 



: thickness ... ... ... ... 1-82 



The single specimen known is not in a very good state of preservation, but 

 the short, almost quite cylindrical, form is so characteristic that the species can 

 be readily distinguished by it. Both the ends are sub-truncate, the anterior slightly 

 convex, the posterior somewhat obliquely obtuse, which form distinguishes the 

 Indian species from Z/«77i. «wZZ«j?a, d'Orb. Portions of the surface of shell only 

 indicate the presence of strise of growth. 



Jjocalitg. — Odium ; found boring in yellowish earthy limestone. 



Formation. — Ootatoor group. 



3. LiTHODOMUS SUB-CTLINDRICA, StoHczka, PI. XXIII, Figs. 18-19. 



Ziith. testa ^3^s^^ZZ//brw^^, cylindracea, postice gradatim compressiitscnla, ad 

 ntramque terminationem siib-rotnndata, umbonibus snb-terminalibus, anticis, parvis, 

 incurvis ; superjicie striis acutis, sulcidis nonmdlis interpositis, concentricis, tecta. 



Length of shell : height ... ••• ... 2'67 



: thickness ... ... ... 2-67 - 268 



The anterior part of the shell is almost perfectly cylindrical, to^nards the 

 posterior end the form becomes laterally compressed, and so far agrees very well 

 with that of Lith. rugosa, d'Orb., but the Indian species wants the peculiar trans- 

 verse striation on the ventral side which distinguishes the European fossil. 



It could be supposed from the imperfect figure given in the Trans. Geol. Soc, 

 Lond., vii, pi. xvi, fig. 7, that Lith. snb-cglindrica is the same shell as Forbes' 

 Mi/tilns cypris, this species having been by European authors also referred to 

 Lithodomvs ; such is, however, not the case, as may be seen by a comparison of the 



