346 CEETACEOUS PELECYPODA 



Mort, are recorded from North America by Meek (Smith. Misc. Coll., No. 177, 1864, p. 8). 

 Which of these species belong to Trigonoarca (and I suppose most of them) remains yet to be 

 ascertained. 



247-257. — Area altirostra, Gabb, Proutiana, Shum,, quindecemradiata, Gabb, Saffordi, Gabb, 

 suielongata, Con., (non A. suhelongata, Nyst, 1848), sulcatina, Evans and Shiim., uniopsis, Con.^ 

 Vancouverensis, Meek, (CibotaJ lineata, Con., (non A. lineata, Goldf.), (Cih.) , muUiradiata, Gabb, 

 and (Cih.) rostellata^ Mort., (Meek, ibidem). In this list the distinction between Barhatia and 

 Area does not appear to have been carried out. 



258-259. — A. Alahamensis, d^Orb., (Prod., ii, 245), A. En/alensis, Gabb, (Journ. Ac. Ph., 2nd 

 ser., iv, 398; see also Nemodon, p. 336). 



260. — Nemoarca cretacea, Con., (see p. 339). 



261. — Nemodon jEufalensiSj Conrad, (see p. 336). 



262-268.— ^rc?« Breiveriana, gravida, decurtata, and Hornii, Barhatia Morsel, CuculUa Ma- 

 thewsonii, and truncata, (non A. truncata, Sow., 1833, non A. truncata, Ess., 1843 = A. curta, 

 Nyst, 1848,) are described from California by Gabb in Pal. Calif, i, pp. 193 et seq. > besides these 

 two others already mentioned. 



%^^,—CiicuUaia inermis, Gabb, (Pal. Calif., ii, p. 271,) is from Mexico. 



^1^-%1Z.—Latiarca transversa, Rog-., Z. ononcheila, Eog., L. gigantea. Con., and 

 Anomalocardia devincta are noticed by Conrad from his lower eocene (? cretaceous) beds (Smith. 

 Misc. Coll., No. 200, 1866, p. 4; see also p. 338). 



274. — Trigonoarca passa. Con., (Am. Journ. Conch., V, p. 43). 



2Th,—Trig. otmeiformis. Con., (ibid., V, p. 98). 



Eomer notes (Kreidebild. von Texas, p. 53,) two not specifically determined forms o^ Area 

 and two of CucuUma from the cretaceous beds of Texas, 



Conrad described in Lynches Exped. the following four species from Palestine, which 

 Fraas (Wiirtemb. Nat. Jahresh., xxiii, p. 233,) partially identifies with known species :— 



^1^'11%.—A. parallela. Con., f=seeuris, Leym.) ; A. lintea. Con., C=cenomaniensis, d'Orb.) ; 

 A. suh-rotundata and faUformis, Con. Farther, Fraas says that Conrad^s supposed Jurassic 

 A. hrevifrons is remarkably similar to A, Passyana, d^Orb. A great many other supposed 

 Jurassic species Fraas rejects altogether, the species having been based upon worthless casts which 

 cannot be again recognised, and there also seems, he says, very little proof existing in favor of 

 the Jurassic age of those species. It is always difficult to determine species satisfactorily from 

 cast specimens, but especially in eases of such thick shells, as the abcin.^ usually possess, the 

 determination of species based upon casts becomes an impossibility. 



The following species of the sub-family arcinm^ have been found in our South Indian 

 cretaceous deposits : 



280-293. ~a^cw//^« (Bquata; Macrodon (? Grammatodon) Japeticum,Macf, (? GTamm.)dispanle; 

 Trigo7ioarca Telugensis, ahrupta, Trichinopolitensis, Gamana, BraJimifiica 2.^^ Galdrhia ; Scapharca 

 Fonticeriana, ? 8capJi. Clellandi ; Barhatia decora, B. diatreta j Area filistriata. They are repre- 

 sented almost equally in all the three sub-divisions of the cretaceous deposits. 



At the end of their review of cretaceous species of Area, Pictet and Campiche, (loc. cit.^ 

 p. 483,) give a list of names which, they say, should be excluded from the genus '' Area,'' as 

 referring to perfectly unknown species. These names are to a great extent merely the altered appel- 

 lations of various species noted in the preceding list; they were introduced by Nyst, but it would 

 have been much better if Nyst had reserved his corrections for a little time, and had studied 

 the various generic forms of arcing, instead of adhering to Linnets genus ''Area'' and 

 simply cataloguing the synonyms of the species described. In his desire to preserve the unity 

 of Linnets genus he even goes so far as to regard Pleurop/iorus of King as identical with Area I 



* Excepting Isoarca gibha already noticed. 



