OP SOUTHEEN INDIA. 175 



usually prominent and pointed; the concentric ribs are comparatively strong; 

 the lunula is very narrow, only indistinctly marked by a shallow depression ; the 

 area is also narrow, but deep. The hinge- teeth offer no peculiarity ; they are 

 short, and the middle one of the three cardinals is the thickest ; the lunular tooth 

 is elongated. This species bears some resemblance to Porbes' Venus Arcotensis 

 fCytlierea), but the ornamentation is totally different. 



Locality, — Ninnyoor, in a white earthy limestone. 



Formation, — Arrialoor group. 



9. Cytheeea [Oallista] discoidalis, Stoliczha, PI. VII, Pigs. 30-31. 



Cytli, testa late sen rotundate ovata^ antice ac infra rotundata^ postice angusta* 

 tim sub-truncata ; declivitate lumilare concaviuscula, areale moderate curvata ; lunula 

 parva^ angusta, impressa ; area longa, angusta, excavata, marginibus acutis circum- 

 data ; fiilcris longis, crassis sed prof unde sitis ; valvis moderate convexiusculis, sub- 

 discoidalibus, liris crassiuscuUs ac interspatiis sub-latis profundis separatis omnino 

 notata. Car do dentibus tribus cardinalibus, brevibus^ in utraque valva crassis 

 instructus ; dente lunulare elongato. 



Length of largest specimen ... ... ... ... 24 m. m. 



Heiglit : length ... ... ... ... 0'87 



Thickness : height ... ... ... ... 0-60 



The more flattened, roundish, and almost discoidal shape of this species readily 

 distinguishes it from the last. The concentric ribs are strong and the interspaces 

 broad, though not as broad as the ribs. 



Locality. — Ninny oor, in a whitish, earthy, and in a conglomeratic limestone. 



Formation. — Arrialoor group, 



i/ 10. Cytherea [Oallista] minutula, Stoliczha, PL VII, Pigs. 18-20. 



Cyth. testa late ovata^ compressiuscula, prope umbones tumescente^ sub- 

 incequilaterali^ antice rotundata, postice angustatim truncatula ; declivitate lunulare 

 concaviuscula^ areale convexa^ ad marginem ventralem regulariter convexa; concentrice 

 eleganter lirata : liris crassis plus minusve obtusis et sulcis csquidistantibus seu 

 interdum latioribus atque subtilissime striatis separatis. Cardo dentibus cardinalibus 

 tribus in utraque valva^ duobus anticis brembiis^ crassiuscuUs, furcatis, postico tenui 

 elongato, et dente lunulare in valva sinistra mediocri, ab ceteris distantiori, fossce pro- 

 fundce in valva dextra congruente instructus. 



Length of largest specimen ... ... ... ... 11"5 m. m. 



Height : length ... ... ... ... 079 



Thickness : height .... ... ... ... 0-52 



This is a very elegant, small, and rather compressed shell, more or less broadly 

 oval, anteriorly rounded, posteriorly slightly and narrowly truncated; only near 

 the beaks the valves are a little more tumescent, flattening out very gradually, so 

 mucli so that larger specimens would no doubt have the appearance of very flat 



