130 CRETACEOUS LAMELLIBRANCHIA. 



geri, d'Orbigny, 1 but the posterior margin is more oblique and the posterior area 

 relatively smaller. 



Remarks. — -The lamellar ribs on the posterior area are not mentioned by 

 d'Orbigny, but attention is called to them by Gueranger. 



J have seen only five specimens, which were collected by the late C. J. A. Meyer, 

 and are now in the Sedgwick Museum, Cambridge. 



G. vindinnensis is the type of Conrad's 2 genus Pachyihaerus. 



Types. — From the Cenomanian of Rouen and Le Mans. 



Distribution. — Cenomanian (Meyer's Beds 10 and 12) of Dunscombe, Devon. 



Genus — Anthonya, II'. M. Gdbb, 1804. 



(' Geol. Surv. California, Palseont.,' vol. i, p. 181, pi. xxx, fig. 236.) 



Anthonya cantiana, sp. no v. Plate XIX, figs. 4, 5. 



Description. — Shell elongate, tapering posteriorly, very inequilateral, much 

 compressed. Anterior margin slightly convex. Ventral margin long, moderately 

 convex. Posterior margin short, truncate, forming angles with the ventral and 

 dorsal margins. Postero-dorsal margin concave. Umbones acute, near the anterior 

 end. A faint carina passes from the umbo to the postero-ventral angle and cuts 

 off a flattened or slightly concave postero-dorsal area. 



Ornamentation consists of numerous narrow, regular, concentric ribs over the 

 whole surface of the shell. The ribs are separated by furrows of greater width 

 than themselves. 



Measurement* : 



(i) (-') 



Length ... 34 .. 27 nun. 



Height 27 . . 14 „ 



(1, 2) Folkestone Beds, near Copt Point. 



Affinities. — This species is distinguished from A. Cornueluina (d'Orbigny) 3 by 

 the shorter anterior part of the shell, the smaller apical angle, and by the ribs, 

 which are of equal or nearly equal strength over the whole surface. It is less 

 elongate and has a smaller apical angle than the type species A. cultriformis, Gabb. 



1 Op. cit., p. 76, pi. cclxv, figs. 1, 2; Gueranger, op. tit., p. 13, pi. xvi, fig. 11. 



~ ' Amor, .loiirn. Conch.,' vol. v (1869), p. 47. 



3 'Pal. Franc. Terr. Crct.,' vol. iii (1844), p. 74, pi. eclxiv, figs. 7 — 9 ; referred to Ptychomya by 

 Pictd and Campiche, ' Terr. Civt. Ste. Croix ' (' Mater. Pal. Suisse,' ser. 4, 1866), p. 357 ; E. G. Skeat 

 and V. Madsen, " Jur. Neoc. and Gault Boulders in Denmark " (' Danniarks geol. Undersog.,' vol. ii, 

 No. 8, 1898), p. 178, pi. vi, fig. 13. 



