OF SOUTHEEN INDIA. 45 



D'Orbigny's figure is probably a little too high, but there are specimens in. 

 our collection which are almost identical with it in form. The most important 

 variations are sufficiently illustrated on plate xvi. 



Locality. — In dark brown sandy and cherty limestone ; north of Odium ; not 

 rare. 



Formation. — ^Ootatoor group. 



V 4. CoKBULA CANCELLiFEKA, StoUczka, PL I, Kg. 17 ; PI. XVI, Pig. 2. 



C. valmila sinistra sub -triangularis antice suh-rotundata, ad marginem inflexa^ 

 postice angustata ac acuminata^ umhone sub-antico, mediocriter prominente, obtuso, 

 antice versus incurvo, carina acuta ab eo ad terminationem posteriorem rectiuscule 

 decurrente instructa ; superficie striis concentricis distantioribus, acutis^ ac alteris 

 radiantibus^ minutissimis ornata. 



Heiglit of left valve : its length ... ... ... 0*67 



Probable thickness of the shell : „ ... ' . . . ... 0-47 



The ornamentation of this species is very peculiar and distinct from that of 

 any other known cretaceous species ; it approaches, however, in this point as well 

 as in its form to some of the recent species, like (7. tunicata^ Hinds, and others. 

 The concentric striae are distant and very sharp, and the radiating lines are very 

 fine and close together ; they are better visible in the grooves than on the strise 

 themselves ; the posterior carina is slightly curved, it is especially sharp and promi- 

 nent near the end; the margin of the shell is anteriorly strongly inflected, very 

 similar to that of C, exulans n. sp. ; the recent species rarely have this inflection 

 equally strong. 



Locality, — In bluish, compact calcareous sandstone near Garudamungalum, 

 in company with (7. parsura^ and a large number of little Qardiidje, Veneeidje^ &c. 



Formation. — Trichinopoly group. 



V 5. OonBULA EXULANS, StoUczlm, PL I, Pigs, 16 and 18 ; PI. XVI, Pigs. 1 and 5. 



O. testa sub-trigona, alta, crassa, compressiuscula, fere cequilaterali, antice sub- 

 rotundata^ postice angustata et sub-acuta, concentrice striata ; umbonibus adpressis, 

 obtusis, parum incurvis ; carina ab umbonibus ad terminationem posteriorem decur- 

 rente prope marginem sita, mediocriter prominente ; valvula dextra sinistra paulo 

 majori. 



Height of shell : its length ... ... ... ... 076 



Thickness „ : „ ... ... ... ... 0*52 



This is a peculiarly triangular, high, nearly equilateral thick shell, laterally 

 much compressed, rounded in front and rather acutely angular posteriorly ; the right 

 valve is somewhat larger than the left one, both being perfectly closed round their 

 margins and inflected towards each other; the entire surface is finely striated. 



M 



