OE SOUTHEEN INDIA. 255 



2. CoRBis OBLONGA, StoUczka, PL XIII, Eig. 10. 



G. testa ovato obtonga, fere cBquUaterali, compressiuscuta, concentrice crasse 

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

 quam in medio ; parte antica tata, ad marginem tente curvata, postica angustiore ; 

 margine areali valde dectivi, rectitisculo, postico subrotundato, margine inferiori, sen 

 'oentrali, undutatim teviter convexo ; lunula elongata, angustissima, Icevigata ; cardine 

 duobiis dentibus cardinalibus et lateralibus instructo, dente laterali antico remoto ; 

 tig amento prof unde sito ; margine interno crenulato. 



Height of shell : its length ... ... ._ __ 0'80 



Thickness „ : „ ■ ... ... .__ ^^_ ().4(j 



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 longer 

 than the posterior. 



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



Formation, — Arrialoor group. 



LUCINA, Brug., 1792, (seep. 249, &c.). 



1. LuciNA [codakia] percrassa, Stoliczka, PL XIV, Eigs. 1-2. 



Lug. ^Cod.'] testa rotundate quadrangulari, sub-cequilaterali, crassissima, 

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

 incrementiet lineis radiantibus intersectis precipue in parte antica distinctis suppeditata; 

 antice late rotundata, postice subtruncafa, infra subrecta seu levissime insinuata ; 

 lunula profunda, ovata ; arecB marginibus declivibus, subrectis, lig amentum prof undum 

 fere omnino tegentibus. Cardine dentibus cardinalibus crassissimis, dente laterali 

 antico crassiori quam postico cardinalibus valde approximate instimcto ; margine 

 interno crasse dentato ; impressione mtiscula7H antica valde elongata, postica ovata ; 

 impressione palliali 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 which equals the present 

 one in the thickness of the shell and its large, ron^ndly quadrangular size. Its 

 external form greatly recalls an Axina^a (= Fectunculus, 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 striae indicating stages of growth, and also some radiating impressed lines, 

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



3 n 



