OP SOUTHERN INDIA. 443 



white, while the smaller valve, exposed to light, is colored. The large develop- 

 ment of the hinge area, with the ligamental groove passing through it, and the 

 structure of the shell of Fedum, undoubtedly show greater affinities to the 

 S]3ondyl% than they do to the Fectines. 



4. Terquemia, Tate, 1867, (Suppl. to Woodward's Manual of MoUusca, 

 Carpenteria, Deslongchamps, 1859, Mem. Soc, Linn., Norm., xi, p. 120— non 

 eadem, Gray, 1856). Valves radiately ribbed, externally lamellar, internally porcel- 

 lanous, rounded, generally somewhat irregular ; right valve larger, attached, usually 

 somewhat convex, left valve somewhat smaller and also flatter; hinge area 

 well developed in both valves, striated, with a ligamental groove passing through 

 it and slightly projecting internally, terminating with a roundish hole ; no hinge- 

 teeth ; muscular scar rounded, somewhat posteriorly placed, excentric, pallial line 

 indistinct; type, Terq. pectimformis, E.-DesL, from the lias. Only a few other 

 Jurassic species have been made known. The classification of the genus in the 

 present place must be considered as provisional, for the shells are extremely like 

 Ostrea, but the hinge area and the ligamental groove appear to me to have their 

 nearest analogues among the Sponbylid^, and the shells themselves show a great 

 similarity to Flicatula, 



List of cretaceous species. 



1. PlicaUtla asperrima, d^Orb., Pal. fran9. terr. cret., iii, p. 679, pi. 462, figs. 1 4. 



2-5.— 7\ Carteroniana, d'Orb., (ibidem, p. 680), Roemeri, d^Orb., (ib., p. Q>^1 -, = armata, 

 Roem., non Goldf.), jplacunea,"^ Lam. (ibid. p. 682; ^ Spond^lus strigilis, Brong.), radiola, 

 Lamek., (ibid]). 683; = ? pectinoides, Sow.). 



6. — P. radiata, Goldf., Petr. Germ., ii, p. 102, pi. 107, fig. 7. 



7.— P. nodosa, Duj., Mem. Soc. Geol. Fr., 1837, ii, p. 228, pi. 15, fig. 14. 



8.— P. inflaba, Sow., (vide Mat. Pal. Suisse.—Foss. de la Pertbe du Rhone, &c., par Pictet et 

 Renevier, 1858, p. 137 ; = P. spinosa, Mant., (Geol. of Suss., p. 26, figs. 13, 16-17; non eadem 

 Sow., sed eadem d'Orbigny, Pal. fran9. cret., iii, p. 685; teste Coquand, Monog. :£tage Apt. de 

 PEspagne, p. 159). 



9.--P. gurgitis, P. and Roux, Foss. des Gres verts, 1849-53, p. 517. 



10. — P. imbricata, Koch et Dunk., Beitrsege, &c., 1837, p. 50, pi. 6, fig. 3. 



11. — P. in(2q%idens, Sharpe, Quart. Journ. Geol. Soc, Lond., x, p. 197, pi. 6, fig. 3. 



12. — P. deUoidea, Tate, Quart, Journ. Geol. Soc, Lond., xxi, p. 39, pi. 3, fig. 5, 



13. — P. as2:)era, Sow., (vide Zittel in Denksch. Akad., Wien, xxv, pt. ii, p. 120, pi. xix, 

 fig. 1, and for further reference p. 446). Fraas (Wiirt. Jahresh., xxiii, p. 232,) quotes the species 

 also from Palsestine. 



14-18.— P^. affinis, Eichw., P. atirita, Trautsch., P.convexa, Eichw., P. rudis, Eichw., et 

 P. lamellosa, Eichw., are all stated to occur in Neocomien rocks of Russia (see Leth. ross., xme 

 livr., p. 413, et seq.). 



19. — P. Araclme, Coquand, (JMon. fitage Apt. de FEspagne, 1865, p. 160). 



20. — PUcahda arachioidea, Desk, Mem. Soc, Linn., Norm., xi, p. 124, belongs to a peculiar 

 genus probably allied to Cyclostreon of the Anomiidje. 



21-22.— P^. clatJirata et delta, Deslongch. (Mem. Soc, Linn,, Normandie, xi, p. 104, pi. 17, 

 figs. 9-10 and 11-12). The second species is considered doubtfully cretaceous. 



* Coquand (Monog. Etage Aptien de I'Espagne, 1865, p. 158), unites asperrima, d'Orb., also with this species. 



