308 NEW YORK STATE MUSEUM 



quity. Surface strongly convex, probably when uncompressed decidedly 

 rotund in the umbonal region. Marginal outline subcircular, extended 

 somewhat posteriorly. The exterior is covered with sharp, broad and flat- 

 tened radial ribs, which are separated by furrows of about the same width. 

 Even in the early stages of growth these ribs are divided in the middle by 

 a depressed area, which becomes more conspicuous with growth, and 

 eventually on the pallial margin attain almost the depth of the intercostal 

 furrows. The margins of the ribs thus divided are sharply erect. From 

 14 to 19 of these duplicate ribs may be counted. 



On the anterior cardinal slope there seems to be a slight variation in 

 the character of these ribs, and, in passing from the ventral to the anterior 

 margin, one of the edges of the double plication appears to be magnified at 

 the expense of the other, with the result that the earliest plications on the 

 cardinal slope appear as simple and alternate in size. A very fine concen- 

 tric ornament crosses all plications and is most sharply developed on the 

 intercostal furrows. 



Length and width of the largest specimen 1 7 mm. 



There is little reason to doubt the identity of this species with P r a e- 

 card, d u p 1 i c a t u m as described and figured by Beushausen. Yet the 

 character of our specimens shows with more force than do those of that 

 author close affiliation of the shell to Buchiola and their deviation from 

 Praecardium in the less abrupt anterior slope, the elevated margins of the 

 plications and the nature of the festooned concentric ornament. 



Habitat. Genesee province ; Chautauqua subprovince. The two speci- 

 mens found are in a dark sandy shale from Johnson's falls, near Strykersville, 

 Wyoming co. 



The German specimens of the species are from the Clymeniakalk of 

 Gottendorf and the Enkeberg, Westphalia. 



Praecardium multicostatum sp. nov. 



Plate 11, fig. 21-24 



Shell subcircular or somewhat oblique but less so than in the other 

 species described. Beak anterior and anterior cardinal slope abrupt. Sur- 



