OF SOUTHEEN INDIA. 255 



2. CoRBis OBLONGA, StoUczka, PI. XIII, Fio-. 10. 



C. testa omto oljlonga, fere ceqiiilaterali, compressiuscida, concentrice crasse 

 costata et radiatim minute striata, striis confertis, autice ac postice paulo fortioribus 

 quam in medio ; parte antica lata, ad maryinem leiite curvata, jiostica angustiore ; 

 margine areali valde declici, rectiuscido, postico subrotundato, margine inferiori, seu 

 ventrali, undulatim leviter convexo ; lunula elon gat a, angustissima, IcBoigata ; cardine 

 duobns deittibns cardinnlibus et lateraUbiis instructo, dente laterall antico remoto ; 

 Ugamento profiinde sito ; margine inlerno crenaluto. 



Iloiglit of shell : its length ... ... ... 0'80 



Thickness ,, : „ ... ... .. _^ O-^l, 



The more compressed valves and the remote anterior lateral tooth essentially 

 distinguish this species from the last. The concentric ribs are strong and sharp, 

 but the radiating strise very fine, and not much more distinct at both the ends 

 of the shell than they are in the middle. The valves 'are nearly equilateral and, 

 what is rarely the case in this genus, the anterior broad end almost a little lono-er 

 than the posterior. 



Locality. — Ninnyoor, in white limestone with the previous species. 



Formation. — Arrialoor group. 



LUCINA, Brug., 1792, (see p. 249, &c.). 



1. LuciNA [codakia] percrassa, StoUczka, PI. XIV, Figs. 1-2. 



Lac. \_Cod.'] testa rottmdate quadrangulari, sub-cequilaterali, crassissima, 

 moderate convexa, sub-lavigata, prope peripheriam striis impressis distantibus 

 incrementiet lineis radiantibiis intersectis prectpue in parte antica distinctis suppeditata; 

 antice late rotundata, postice subtruncata, infra subrecta seu leoissime insiniiata ; 

 lunula jirofunda, ovala ; arece margin ibus declivibus, siibrectis, ligamentmn profundiim 

 fere omnino tegenlibus. Cardine dentibus cardinalibus crassissiniis, dente laterali 

 antico crassiori quam postico cardinalibus valde approximato instructo; margine 

 interno crasse dental ; impressione musculari antica valde elongata, postica ovata ; 

 impressione palliuli profunda, continua. 



Height of shell equal to its length, or very little longer ; thickness equal to half the length, or a little more. 



There is scarcely another species of Lucina known wliich equals the present 

 one in the thickness of the shell and its large, roundly quadrangular size. Its 

 external form greatly recalls an Axincea f^^ Pectunculus, Lam). Some of our 

 largest specimens are 150 m. m. long, and the shell near the beaks is sometimes 

 20 m. m. thick ; naturally the hinge-teeth are also very strongly developed ; the 

 anterior lateral is much stronger than the posterior and quite close to the cardinals. 



The external surface is almost smooth in the greater number of specimens, 

 but when well preserved it shows towards the margin a number of distant con- 

 centric strise indicating stages of growth, and also some radiating impressed lines, 

 which are generally most distinct on the broader anterior end. Tlie internal 



3 R 



