New Species of Paleozoic Fossils. 177 



P L AT Y STOMA, Conrad. 

 Platystoma niagarense, var. multilineatum, n. var. 



PLATE II., FIGS. 4 a-C. 



Platystoma niagarense. Hall, Twenty-Eighth Report on the State Museum, p. 

 175, Plate 28, Figures 1-4. Not the specimens of P . niagareuseSWw'iX.xdXQ.il by 

 other figures in the same report, nor those in Pal. N. Y., Vol. II. 



Among the specimens of Platystoma from Waldron, In- 

 diana, there is occasionally one conforming in outline to the 

 typical specimens of P. niagarense^ Hall, but differing in hav- 

 ing the lines of growth, usually so prominent in this species, 

 suppressed more or less completely, and the surface of the 

 shell ornamented with well-defined, regular, equidistant re- 

 volving striae. The form illustrated on Plate II., Figures 

 4 a-c, has* the revolving striee very perfectly developed, and 

 the Hnes of growth are completely obsolete, so that the sur- 

 face of the shell presents not even a sugciestion of cancellation. 

 Were the two types of Platystoma found in different localities, 

 without intergrading forms, the characters in respect to which 

 they differ would have specific value. The form is so distinct 

 from the normal type of P. niagarense^ that it will be con- 

 venient to have some ready means of designating it by name, 

 and so I propose to separate it as variety multilineatum. 



H O L O P E A, Hall. 

 Holopea grandis, n. s. 



PLATE III., FIGS. I a, b. 



Shell very large, ventricose, subconical; spire moderately 

 elevated; whorls three or more, orbicular in cross section, lax 

 in cast of the interior of the shell, increasincj reffularlv and 

 somewhat rapidly in size; aperture nearly circular; umbil- 

 icus, judging from the cast, relatively wide and deep; surface 

 unknown. 



Holofea magniventra., Whitfield, from, the Guelph limestone 

 of Wisconsin, is a large form allied to H. grandis. The pres- 

 ent form, however, will be distinguished from H. magniventra 



