683 Plat, 



Resembles P, gebhardi. Lower Helderherg. VI, 



Platyceras varians, new spec. Simpson, Trans. Amer. 

 ^;jj,. Philosoph. Soc. Philada., 1889, page 458, 

 fig. 28 ; species based on Randall's specimens 

 9471, 9472 B. — Shell small, subcorneal, curved, 

 slightly oblique ; apex not incurved or bent; 

 width at the base two-thirds the length of the 

 anterior side, and about equal to the posterior. 

 Plications frequent, variable in number. On 

 the dorsum there is sometimes a faint indication of a carina; 

 on the left side is a deep conspicuous furrow, which extends 

 about three-fourths the length of the shell from the base; be- 

 yond this there is a slighter furrow ; the area between them 

 elevated, rounded and very prominent. On the posterior side 

 of the shell are usually two or three slight furrows, but occasion- 

 ally a stronger one, and on the left side there is one nearly as 

 strong as on the opposite side. Sometimes on the posterior 

 side the area between two of the smaller furrows is elevated, 

 having the appearance of a ridge or carina, which is occasion- 

 ally prominent. The deep furrows on the right and left sides 

 of the shell appear to be constant features, the others are some- 

 what variable. Aperture broadly oval, nearly circular; peri- 

 stome concealed on all the specimens observed, so that its true 

 form cannot be ascertained. All the specimens occurring in 

 the form of casts, the surface markings are obsolete. This 

 species may be distinguished from Platyceras mitelliforme by 

 its slraighter form, absence of a prominent carina, by its con- 

 spicuous plications; from P. (0.) striatum by its smaller size, 

 more frequent plications, and the absence of radiating striae, 

 the convexity of the anterior side and the concavity of the 

 posterior; from Platyceras inequale by its equally developed 

 right and left sides and its conspicuous plications; from P, 

 ( 0,) hreve by its curved, more slender form, and plications ; 

 from Platyceras dorsale by its smaller size and conspicuous 

 plications; from P. (0.) attenuatum by the straight apex and 

 the strong lateral furrows ; from Platyceras carinatum by the 

 absence of a prominent carina and by the conspicuous lateral 

 furrows ; from P. (0.) conicum by its smaller size and curved 

 form. — Four miles north-west of Warren, Warren county, 

 Pennsylvania, in Chemung upper beds. VIII y. 



