OF SOUTHERN INDIA. 329 



3. NucuLA, sp. ind., PI. XVII, Pig. 20. 



The figure represents an evidently larger and more sub-trigonal shell than 

 N. indefinita ; the anterior muscular impression is very faint, the posterior some- 

 what better marked and rounded ; the cast shows 18 anterior and 10 posterior 

 teeth on the hinge-margin ; the latter are longer, but thinner than the former, and 

 the denticulation is barely interrupted under the beaks by a pit which must be 

 small and situated quite internally. 



Locality,— OAium ; only the single figured cast specimen was found, and as 

 there are no traces of the shell surface preserved, I will not now designate it 

 with a specific name; it bears some relation to Nils son's ovata. 



Formation. — Ootatoor group. 



4d. NucuLA CHASSICULA, Stoliczka, PI. XVII, Pig. 23. 

 N, testa suh'trigona, crassiusciila, moderate tmnida, supra lente, infra majm 

 convexa, antice ad terminationem angustatim rotundata interdiimque sub-angulata, 

 postice brevissima, oblique truncata, area Mud distincter marginata, latiuscula, ad 

 medium paulo elevata ; superficie striis concentricis crassiusculis, confertissimis , 

 nonnunquam 2-3 sulcis profundis distantibus ad medium et ad peripheriam sitis, et 

 striis radiantibus minutis plus minusve dislinctis intersectis notata ; cardine multU 

 dentato, dentibus fovea parva infra umbones sita interruptis ; margine interno eras- 

 se denticulato. 



Height of shell : its length ... ... ... 0*75 - 078 



Thickness „' : „ ... ... ... 0-41 - 0-46 



This is a remarkably strong shell as compared with its size, and some specimens 

 are conspicuously more convex than the one figured. The very close concentric 

 striation is often interrupted about the middle and near the periphery with two or 

 three deep furrows ; they only indicate stages of growth, and are, therefore, occasion- 

 ally absent. A fine radiating striation is also traceable on the entire surface in 

 well preserved specimens, but in others it remains only posteriorly distinct, or in the 

 furrows separating the concentric striae. The internal pearly layer is externally 

 very finely striated. 



Locality, — Karapaudy, in whitish coarse sandstone ; not uncommon. 



Formation. — Arrialoor group. 



5. NucuLA BiDOUSATA, StoUczha, PL XVII, Pigs. 22, 24-27. 

 N. testa parvula^ elongato ovata, antice late rotundata, postice brevissima, oblique 

 Totundate sub-truncata, area ad medium valde prominente ; valvis paulo convexis, 

 superficie concentrice et radiatim crasse striata ; margine interno denticulato ; 

 cardine dentibus numerosis, parviilis, fovea infra umbones interruptis, instructo. 



Height of shell : its length ... ... ,.. ... 074 



Thickness „ : „ ... ... ... ... Q'SS 



This species is closely allied to the last, but it is more regularly ovately elon- 

 gated, somewhat more compressed towards the margins; the area is less truncate and 



