PANOPBA. 229 



Affinities. — Tlie more elongate forms of this species resemble some specimens 

 of /'. (in)-(jitis var. pUcata, but are more inetiuilatcral, more convex, usually 

 relatively longer, with narrower and more pointed unibones, and with a distinct 

 furrow extending from the undjo to the postero-ventral margin. 



Uemarks. — Many of the specimens are more or less crushed, and nearly all are 

 internal casts, but the shell is preserved in some specimens from the (lault, and 

 shows radial rows of fine granules. The hinge is not seen in any instance. 

 P. mandilnda is common in the Upper Greensand of Ventnor and Devizes, and is 

 less abundant at other horizons. The principal variation seen is in the relative 

 length and heio-ht of the shell. 



Type. — From the Upper Greensand of Devizes, in the British Museum. 



Distribution. — Lower Greensand of Atherfield. Atherfield Beds of Seveuoaks. 

 Sandgate Beds of Nuffield. Folkestone Beds of Folkestone. Upper Greensand 

 (zone of SrJihvnhachia rostrata) of Devizes and Yentnor. Gault and Upper 

 Greensand of Black Ven. Chalk Marl of Folkestone. 



Panopea ovalis, Soicerhij, 18:36. Plate XXXVII, fig. Q>a,h. 



1836. Panopea ovalis, J. cle C. Sowerby. Traus. Geol. Soc, ser. 2, vol. iv, pp. 



241, 340, pi. xvi, fig. 5. 

 1850. — — A. iVOrhiijny. Prodr. cle Pal, vol. ii, p. 157. 



1854. Myacites — /. Morris. Cat. Brit. Foss., ed. 2, p. 214. 



Description. — Shell oval, convex, moderately inequilateral. Antero-dorsal 

 margin slightly convex ; anterior margin rounded, passing gradually into the 

 slightly convex ventral margin. Unibones broad, incurved. The parts of the 

 shell in the front of and Ijehind the umbones are considerably dejjressed. The 

 surface is ornamented with growth-rings. 



Remarls. — The only specimen seen is the t\'pe, in which the posterior part of 

 the shell is not preserved. 



Tijpe.- — 111 the British ]\Iuseuiii. 



Distribution. — Upjier (ireensand (zone of Schluinbackia ro.ftratu) of Blackdown. 



P.\xoPE.\ Meyeri, sp. nov. Plate XXXVIII, fig. la,b. 



Desiuiptiun. — Shell oval, moderately convex, witli flattened sides, slightly 

 inequilateral, with a wide posterior gape. Antero-dorsal margin convex. Anterior 



