OF SOUTHERN INDIA. 461 



4. ExoGYRA FAUSTA, Stoliczko, PL XXXVIII, Eigs. 4—5; PI. XXXIX, 



Eigs. 3 — 5. 



Ex. testa ii-ref/ulariter ovato elongata aut siib-quadrata ; valva inferlore aut prope 

 ambouem, ant magna parte lateris ventrallsi sessili, gibboso convexa, prope medium 

 muxime elevata, radiatim costata : costls sparsis, scepe dichotomis, lamellis conceu- 

 tricis irregularibus interruptis, aut qctite rugatis ; umboue modice promimilo, valde 

 intorto, apice depressiusciilo, indistincto ; fovea ligamentall longa, angusta, stib- 

 marginali, eurvata, ad ajncem sitlcum elongatum, denteni valo. alterce recipientem, 

 earente ; impress, muse, late ovulata, antice fvel supra J truncata, haud procul 

 (lb nmbone sita ; marg. pall, pone termlnationem fovece ligam. breviter crenulato ; 

 calv. superiore undulate planata, concentrice sub-rugosa et ad marg'mem concexum 

 paulo incrctssata et undulate lamellosa. 



The form of the shell of this species is very variable, the larger valve being 

 either only with a small portion of the beak sessile or with nearly the Avhole of 

 the lower half. According to the amount, or place, of attachment the gibbosity of 

 the larger valve is more or less regular. The surface is marked Avith compara- 

 tively few, irregular, often divided ribs, which are intersected by strong concentric 

 ■ lamellae of growth, mostly prominent on the ribs. Near the margin the ribs 

 become obsolete or very nearly so. The smaller valve is usually somewhat undu- 

 lating, smooth or covered with a few concentric rugosities, and at the convex 

 margin it is always more thickened and lamellated. The only species which can 

 be compared in general character with the Indian fossil is Exog. Oltsojwnemis, 

 Sharpe, from Portugal (Coquand, Mon. Ostr. cret., p. 125), but in this species 

 the ribs are still less in number on the larger valve, and its beak is nuicii more 

 prominent and more strongly spirally incurved. 



Locality. — Anapaudy, in a brownish sandstone. 

 ^ " Formation. — Trichiuopoly group. 



5. ExoGYRA COSTATA, Saij, PI. XL, Eigs. 1 — 3 ; PI. XLI, Eig. 1. 



1821. Exogyra costata, Say, Am. Jouni. Sc. and Arts, ii, p. 53. 



1834. E. costata et /Ostrea torosa, Morton, Syuop., pp. 50 and 55, pi. vi, tigs. 1-4, and pi. .k, tig. 1. 



1869. Ostrea torosa, apud Coquaud, Mon. Ostr. cret., p. 38. 



Ex. testa rotundate ocata ; valva majore inflata, umbone valde intorto, later- 

 aliter sessili, concentrice lamellate striata et radiatim costulis irregularibus, confertis, 

 partim undulatis, scepe interruptis et dichotomis, ornata ; oalva minore plana, concen- 

 trice striata, nonnunquam costulis nonnnllis radiantibus tecta ; impjressione musculari 

 prope umbones sita, excavata, transversaliter sub-ovata ; fovea ligamentali longa, pro- 

 funda, angusta, marginali, lente eurvata, infra acute marginata et area rugulosa 

 sub-triangularl sub-posita. 



I can see no difference between specimens from South India and those from 

 North America ; smaller and larger specimens perfectly agree in form, in the 



5 w 



