342 CRETACEOUS PELECYPODA 



eS9-43. — JiT. hamula, Mort.j Siouxensis, Hall and M., sithve^itricosa, M. and Hayd., rotundata 

 Gabbj and sulaustralis, d'Orb._, are noted by Meek from North America in Smith. Misc. Coll. 

 No. 177, 1864, p. 8. 



44-46. — Ax, Yeatchn, sagittata^ and cor are described by Gabb from California, (Pal. Calif, i, 

 1864, p. 197 et seq.). 



47. — Ax, Morio7ii, Conrad, from New Jersey, (Am. Journ. Conch., V, p. 44). 



Eichwald (Leth. ross., xme livr., 1867, p. 576), suggests that Keyserling-'s Tectunmdus 

 Fetsclwrce may be a Neocomien species of Axin^Ba. 



48-53. — Nucinella glahraia, Axincea suhplanata, levicula, altiusculaj suhauriculata, and cardioides 

 represent this sub-family in the cretaceous deposits of Southern India. 



b. arciNjE, 



Pictet and Campiche note the species belonging to the present sub-family under the genera 

 Isoarca and Area (vide Pal. Suisse, IV^^ ser., 3"^® part., pp. 423 and 429 et seq.) ; I shall, therefore, 

 take the first genus and then the second, in which it will be necessary to point out the different 

 generic and sub-generic forms, as distinguished by later researches, and as far as admissible from 

 existing materials, 



54-58. — Isoarca alpi7ia, glohiilosa, Agassizi, eostata, ohesa,^ and supracretaeea. 



59. — Isoarca gihha is the only species occurring in Southern India ; no species is known to re- 

 present the genus in America. 



Area and allied genera (see Pictet and Camp., 1. cit., p. 468). 



60. — Area marullensis, d^Orb., Baudoniana, Cott., episcopalis, Cott., Auhersonensis, P. and C. 

 Duhiesiensis, P. and C, and Dupiniana, d^Orb., are Barhatm, 



61. — A. Jaccardi, P. and C, belongs to the sub-genus Acar, 



62-63. — A. Essertensis and Humlertlna, Loriol, (Favre Res. geol. de la Savoie, &c., pi. C 

 figs. 16 and 17,) belong either to Area, or perhaps rather to the sub-genus Calliarea. 



64-66. — A. sanctce-erucis, P. and C, Cartero7ii, d^Orb., eomjQla7iata, P. and C, (non A, com- 

 planata, Chem., 1784, non Cueul. eomplanaia, Sow., 1840), 



67. — A. Raulini. Leymerie^s original figure would indicate a -i&^?'3<^?^?^, with fine radiating 

 striae and broadly incurved, somewhat flattened, beaks ; d^Orbigny^s figure, supposed to be the 

 same species, would seem rather to represent a Cucullcea-\\kQ shell, somewhat of the form of a 

 Trigonoarca or Nemodon. Either one or the other of these figures must surely be incorrect, or they 

 represent two distinct species. 



68. — A. 'N eocomiensis , d^Orb., may belong to the section called Nemodon by Conrad. 



69. — A. securisj Leym., is apparently one of the elongated forms of Scapharca, called by 

 Conrad Nemoarca. 



70. — A. exsculpta, Koch, appears to be a Barhatia. 



71-75. — A, Schusterij Rom., Bohinaldma, Cornueliana, and consohrina of d''Orbigny, and 

 ViUerse7isis, P. and C, are most probably TrigojioarccB. 



76-83. — A. Moreana, d^Orb., GadrieliSj'Lejm.jt74mida,'Msiih.. ( ?=^Gahrielisj Leym.), ^crand 

 Astieriana of Matheron, Qresslyi and Salevensis, Loriol, Varusensis, d^Orb, The last is quite 

 insuflftciently characterized; the two first ones are probably true CiicidlcBCB, and the others Pictet and 

 Campiche suggest may all be varieties of A, Gahrielis ; the descriptions and figures puWished of them 

 are quite insufficient to enable an opinion to be formed as to the specific characters of these shells. 



84. — A. ferruginea, (non A.ferruginea, Reeve, which is an Anomalocardia) , is either a Cucullcea, 

 or it belongs to the sub-genus GramwModon, 



* r=: Isocardia Orhignyana, Leym. =: Area isocardiiformif!, Nyst. 



