PANOPEHA. 229 
Affinities.—The more elongate forms of this species resemble some specimens 
of P. gurgitis var. plicata, but are more inequilateral, more convex, usually 
relatively longer, with narrower and more pointed umbones, and with a distinct 
furrow extending from the umbo to the postero-ventral margin. 
Remarks.—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 Gault, and 
shows radial rows of fine granules. The hinge is not seen in any instance. 
P. mandibula 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 height of the shell. 
T'ype.—From the Upper Greensand of Devizes, in the British Museum. 
Distribution.—Lower Greensand of Atherfield. Atherfield Beds of Sevenoaks. 
Sandgate Beds of Nutfield. Folkestone Beds of Folkestone. Upper Greensand 
(zone of Schlanbachia rostrata) of Devizes and Ventnor. Gault and Upper 
Greensand of Black Ven. Chalk Marl of Folkestone. 
PANOPEA OVALIS, Sowerby, 1836. Plate XXXVII, fig. 6a, b. 
1836. Panopma ovatis, J. de C. Sowerby. Trans. Geol. Soc., ser. 2, vol. iv, pp. 
241, 340, pl. xvi, fig. 5. 
1850. — —  A.dOrbigny. Prodr. de Pal., vol. 11, p. 157. 
1854. Myactres — J. Morris. Cat. Brit. Foss., ed. 2, p. 214. 
Description.—Shell oval, convex, moderately imequilateral. Antero-dorsal 
margin slightly convex; anterior margin rounded, passing gradually into the 
shghtly convex ventral margin. Umbones broad, incurved. The parts of the 
shell in the front of and behind the umbones are considerably depressed. The 
surface is ornamented with growth-rings. 
Remarks.—The only specimen seen is the type, in which the posterior part of 
the shell is not preserved. 
Type.—tIn the British Museum. 
Distribution.—Upper Greensand (zone of Schlanbachia rostrata) of Blackdown. 
PanopeA MeEyeERI, sp. nov. Plate XXXVIII, fig. la, b. 
Description.—Shell oval, moderately convex, with flattened sides, slightly 
inequilateral, with a wide posterior gape. Antero-dorsal margin convex. Anterior 
