OP SOUTHERN INDIA. 433 



Similar differences also apply in a comparison with other allied species, as for 

 instance, P. Dujardmi, Roem., rarispinus^ Heuss, and one or two others des- 

 cribed by Goldfuss. 



The ornamentation of asperulinus is, however, very variable on account of the 

 scales being easily broken oflp. The median tubercles are often quite worn away, 

 and the lateral ribs become more or less indistinct, except the two lowest (comp. 

 fig. 10 on pi. xxxi), which are seated in the cavity between the ribs. 



Localities,-— Nq^v Kaudoor, in a white conglomeratic sandstone, and near Choka- 

 nadapooram, in a whitish soft limestone. 



Formation, — Arrialoor group. 



It deserves to be noticed that in the Ootatoor limestone at Cooticaud there 

 occurs another still larger species, probably belonging to the sub-genus Chlamys, 

 It is apparently a little higher than Fecten depressus, Miinst., (Goldfuss, Petrsef. 

 Germ., pt. ii, p. 53, pi. 92, fig. 4). The ribs are broad, carinate in the middle, 

 with a few radiating striae at the sides, and one more distinct in the groove separ- 

 ating each two large ribs. None of the specimens are, however, sufficiently perfect 

 to define the exact form of this interesting species. 



6. Pecten [Camptonectes] curvatus, Geinitz, PI. XXXI, Pigs. 15—16. 



PI. XLI, Pigs. 4—6. 



1827. ? Pecten arcuatus, Sow., apud Nilsson, Petrif. Suec, p. 22, pi. ix, %. 14, non idem Sowerby. 

 1843. „ curvatus, Geinitz, Kieslingsw., p. 16, pi. iii, fig. 13 ; et 1848, Quadersandst., p. 180. 



1845. „ virgatus, Nilss., apud d'Orbigny, Pal, fran9. terr. cret., iii, p. 602, pi. 434, figs. 7-10, non 



virgatus, Nils son. 

 184.6. „ virgatus, Nilss., apud Forbes, Trans., Geol. Soc, Lond., vii, p. 154, pi. xv, fig. 22. 



1846. „ arcuatus, et ? divaricatus apud Eeuss, Boebm. Kreidef., pt. ii, pp.27 and 28, pi, xxxix, 



figs. 6 and 7. 

 1850. „ suhvirgatus, d'Orbigny, Prod., II, p. 253. 



1866. „ virgatus, Nilss., apud Zittel, Denkscb. Acad., Wien, xxv, pt. ii, p. 109, pi. xvii, fig. 8, (baud 



synon. omnibus). 



F, [ Camp,'] testa suh-orhiculare ovata, prope apicem sensim angustata, sub-cequi- 

 valvi, valva sinistra paululiim convexiore, utraque radiatim confertissime striato- 

 costellata, costellis depressis, in valva dextra tenuiorihus quam in sinistra, excurvatis, 

 plurime dichotomis, lineis impressis multo angustioriUis, punctatis, separatis, et striis 

 imcrementi concentricis minutis intersectis ; auriculis radiatim striatis aut costellatis, 

 incequalibus, postica minore, oblique truncata, antica majore, in val, dextra ad basin 

 profunde insinuata. 



The right valve is in this species always somewhat flatter, and the radiating strise 

 are, as a rule, finer on it than on the left valve ; the ears are marked with oblique 

 transverse striae, which become on the anterior ear of the right valve mostly obsolete, 

 being replaced by concentric arcuate striae. Zittel published a few years ago a 

 long account of the synonymy of Fecten virgatus, Nilsson, but his discrimination 

 of the various forms does not seem to be always correct. I shall briefly notice the 

 history of the present species and of virgatus, 



5o 



