OF SOUTHEEN INDIA. 355 



lengtli, but it always does so in its thickness, the ligamental area becoming very 

 broad and rather closely angularly sulcated. In this stage some of the specimens, 

 as, for instance, the one represented in fig. 3 of pi. xx. are so remai'kably like the 

 European Trig. Mather oniana, d'Orb., that I do not think their identity by any 

 means improbable, but unfortunately I have no typical specimens for comparison. 

 The hinge-teeth of Brahminica are also very similar to those of Ilatherouicma. 

 There are four or five oblique teeth on either side below the angle ; the median 

 hinge-teeth become very small towards the middle, sometimes they are nearly obso- 

 lete, the hinge-line itself being thin, and in this respect strongly differs from that of 

 Triff. Gamana. 



Localities. — Neighbourhood of Karapaudy, Arrialoor, Mulloor, Comarapol- 

 liam, &c., mostly in a coarse sandstone ; not very common. 



Formation. — Arrialoor group, of which the species appears to be equally 

 characteristic, as is TrichiiiopoHtensis of the Trichinopoly and Gamana of the 

 Ootatoor group. 



6. Trigonoarca Galdrina, d'Orbigmj, PI. XVIII, Figs. 2 — 5. 



1847. Area Galdrina, d'Orb., Voy. Astrolabe, Paleont., pi. v, figs. 32-33 — eadem auctorum. 



Trig, elongate trapezoidali, incequilaterali, moderate injlata, antice stih-rotundata, 

 postice carinata et valde producta, oblique trimcata ; area mediocri, angulatim 

 striato-sidcata ; superficie concentrice filiforme striata; declivitate postica prope 

 medium latisulcata et striis radiantibiis nonnidlis, supra circiter 8, ivfra ad carinam 

 4-5, tecta ; cardo dentibus numerosis sicut in speciebus tgpicis instructus. 



Height of shell : its length ... ... ... .,. 055 



Thickness „ : „ ... ... ... ... 048 



A markedly elongated form, slightly iuequivalve, the left valve being a little 

 larger. The striae on the surface often become almost quite obsolete, in which 

 state the shell shows a great similarity to Trig. Gamana, being distinguished from 

 it merely by the more elongated form and comparatively less narrowed anterior 

 side. The posterior radiating ribs near the carina are very characteristic. 



Locality. — East of Scrdamungalum and near Stripermatur, in a soft whitish 

 sandstone. 



Formation. —Kxvhloor group. 



ANOMALOCAEDIA, Klein, [SCAPHAECA, Gray, 1847] (see p. 339). 

 1. Anomalocarbia [Scapharca] Ponticeriana, d'Orbigny, PL XVII, Fig. 39, 



PI. XVIII, Fig. 1. 



1847. Area ponticeriana, d'Orb., Voy. d'Astrolabe, Paleont., pi. v, figs. 29-31, — eadem auctorum. 



Scaph. testa valde elongata, fumida, antice oblique rotundata; postice sub-cari- 

 nata, declivitate prope medium sub-sidcata, ad terminationem oblique truncata, 

 incequivalvi, valva sinistra pjaulo majori ; sup)erjicie radiatim costulata, costiilis 



4s 



