76 CRETACEOUS PELECYPODA 



Ph. interrnpfa , Ph. consobrina, Ph. dllatata, Keyserling', Ph. Borrissuk'd, Ph. nar'u-nlaris, 

 (CARDiss.); — Ph. costijera, Ph. iaurica, the last two species have an internal ridge running ob- 

 liquely from the beaks towards tlie peripliery, like in most of the FIIOLADIDM. 



153-154. — Ph. Barrassi (not Barrassi ns entered by Pictet and Campiche) and Molli of 

 Coquand are two species which rather belong to Poromya or Plenrowya than to Pholadomya. 

 A few species may be added from Africa, if any of those now considered Jurassic deposits, but pro- 

 nounced by Krauss to be cretaceous, should turn out to be of the latter age. 



155-164f. — Meek (Smith. Misc. Coll., No. 177,) quotes from North America Homomya alta, 

 (may also be a Poromya), Ph. tlegnndda, occiflenfalig, papyracca, Buhreniricosa, mihelonguia, ttima, 

 ( — is .''), (exana, tippana, and Ph. ( Cymella) unda(a ; besides Ph. pedernalis and umbonaia, Rom., 

 which have already been mentioned. 



165-16G. — Goniomya americaiia and lorenlis, (ibid.). 



1G7-172. — Gabb (Pal. Calif, i, p. 152, &c.,) describes Ph. Brewerii (multic), — Ph. nasnia, 

 ( CARDISS.), — Horn, concentrica, Gabb, Arcomya undulata, Pleuromi/a papyracea, and Ph. Orego- 

 nensis, Gabb, (Pal. Calif ii, p. 235-236). 



173. — Ph. sandi-saba,, Riimer, (Texas, Cardmrn id., p. 48). 



174. — Pachymya Austinensts, Shumard, Trans. Acad., St. Louis, 1S6(J, p. C04. 



175-176. — Ph. syriaca and decisa, Con. (Off. Report in Lynch's Exped. to Palestine; see also 

 Fraas in Wiirtbg. Nat. Jahreshefte, xxiii, p. 23S). 



177-180. — In the South Indian cretaceous deposits four species occur. Ph. caudata is identical 

 with the European species; another was named by Forbes connecians; the two others are new. 

 Ph. radiaiula and pedisulcata ; the first of these belongs to the type of Ph. rostrata ; the second is 

 a peculiar elongated form with the front sides sulcated, and gaping. 



Thus, we observe from this very brief revieAV that the cretaceous beds possess 

 nearly as great a variety of generic types of the Anatinidje as do the jurassics. 

 The genera which are sufficiently well known are Thrac'm, Corimya, and very pro- 

 bably Per//)^ow«a and Asthenothoirns ; Anatina (with Cercomya, Anathnya, Flecto- 

 mya, and perhaps Flatymya) ; Ceromya, Goniomya, Fholachmya, Ilyacites, and very 

 probably Homomya and Fleuromya. Several species described as Pholadomya, but 

 most likely belonging to Poromya, still have to be separated from the great number 

 of true PholadomycB. 



CORIMYA, Agassiz, lSi2 (see p. 63). 



1. CouiMYA Oldhamiana, StoUczka, PI. II, Figs. 14-15. 



Cor. testa oblonr/n, compressiuscula, tenui, postice (niffuste hianti, iiicpqiiUaferali, 

 parte postlca hreolori quam antlca ad marginem snperiorem mvlto compt^essa ; 

 utrinque lente rotundata ; umbonibiis prominuUs, postice versus ciirvatis, in parte 

 2')Osteriori distincte fissuratis : Jissura obliqua, ejusdem margitiibus inversis titmes- 

 centibiis, postice sed juxta hanc fissitram costa crassiiiscula dimidio altitudinis testa 

 equante sita ; sitperficie concentrice striata ac lineis interruptis radiantibus per- 

 tenuibus induta ; vulva sinistra paitlo majori quam dcxtra. 



Height of shell : its length ... ... ... ... O'ol 



Thickness „ : „ ... ... ... ... 0-26 



The external calcareous layer of the shell which is very finely concentrically 

 striated is thicker than the inner nacreous layer, on which, however, some short 



