OF SOUTHERN INDIA. 349 



4. AxiN^A SUBAURICTILATA, Fovbes, PI. XVII, Figs. 31-32. 



1846. Pectunculus suhauricalatus, Porb., Trans. Geol. Soc, Lond., vii, p. 150, pi. xvii, fig. 13; — idem auctorum. 



Ax. testa suh-rotundata, cequilaterali, pauluhim obllqua, crassa, j^ostice ad inm'- 

 ginem suh-tmncata, infra medium siib-angidata, tumida, radiatim costulata, costuUs 

 covfertis ; area 2Jarva, valde declki ; cardine dentihus elongatis, Q-\0 in utroqne latere, 

 et circiter decern intermediis, minoribus, instructo ; margine interno denticidato. 



Height of shell : its length ... ... ... ... 104 



Thickness „ : „ ... ... ... ... 0-68 



Distinguished from tlie next species by its rounder shape, smaller and more 

 precipitous area, and closer radiating ribbing. 

 Locality. — Kunnanore, in grey sandstone. 

 Formation. — Arrialoor group. 



5. AsiN^A CAKDioiDES, d'Orbigwj, Tl. XVII, Fig. 33, PI. L, Fig. 8. 



1847. Area cardioides, d'Orb., Voy. Astrolabe, Paleont., pi. iv, figs. 35-36; — eadem auctorum. 



A.::, testa siib-rotundata, paulo longiore quam alta, tmnida, sub-cequilaterali, 

 obliqua, postice plus minusce distincter producta et siib-trmicata, radiatim costulata, 

 costulis in declivitate antica et postica fere obsoletis, in medio sulcis aut cequidistan- 

 tibus aid angustioribus separatis, nonmmquam siib-granosis, ornata ; nmbonibus j^t'o- 

 minentibus, inci(,rvis ; area ligamentali magna, moderate declivi ; cardine crasse et 

 jMciforme multidentato. 



Height of shell : its length ... ... ... 0-86 - 0-90 



Thickness „ : „ ... ... ... 076 - 0-78 



There are slight variations to be observed in the form and ornamentation of 

 this species. D'Orbigny figured a comparatively very inequilateral and oblique 

 specimen from Pondicherry ; we have exactly similar specimens from Ootatoor and 

 Odium, (see pi. 1, fig. 8). Another specimen from the same locality and one from 

 Serdamu-ngalum out of a conglomeratic calcareous rock are somewhat less produced 

 posteriorly, and the radiating ribs are a little more distant from each other, than 

 is generally seen in Ootatoor specimens, but there is no appreciable specific dis- 

 tinction between the two forms. Although the shell is somewhat oblique, the dis- 

 tribution of the hinge-teeth clearly shows that it belongs to Axincea. 



Localities. — Pondicherry, Ootatoor, Odium, and south-east of Serdamungalum. 



Formations. — Ootatoor and Trichinopoly groups, 



ISO ARC A, Milnsfer, 1842, (see p. 338). 



1. IsOARCA GLBBA, StoUczka, PI. VIII, Fig. 8, and PI. XVII, Fig. 36. 



I. testa trapezoidali, valde gibbosa, temti, siib-inmqtiilaterali, antice rotundata, 

 2)0stice paulo producta, oblique convexe truncata ; umbonibus valde incur vis, approxi- 

 inatis ; superficie minute reticulata vel decussata, striis filiformibus, concentricif. 



