GASTEROPODA. 
99 
specimen figured on plate 22, as well as others examined, are so far eroded or 
exfoliated as to have lost the evidence of the dorsal band, and that they are in 
fact the B. Newberryi. 
Belleropiion hyalina, n. sp. 
PLATE XXVI, FIG. i. 
Shell subglobose, rounded upon the dorsum, and very abruptly depressed into 
the comparatively broad umbilicus. Body-wliorl ventricose and rapidly 
expanding. Aperture very wide, broadly reniform — the full extent 
unknown; margin undetermined; the outer lip recurving at the sides, 
and partially inclosing the broad umbilical depression, and spreading in a 
thin callus over the columellar lip. 
Surface marked by somewhat distant, sharp, transverse striae which bend 
backward as they approach the centre of the dorsum; and these are 
cancellated by finer revolving striae. No dorsal band has been observed. 
The general aspect of the surface is like that of a young individual of B. 
Leda, but the broad umbilicus, with the subangularity of the sides of the outer 
volution are distinguishing features. The shell is silicified and crystalline, and 
the surface-markings pretty well preserved. Although no dorsal band has been 
observed, it is possible that such a feature may exist in better preserved 
specimens. 
Formation and locality. In some decomposing cherty layers in the upper 
part of the Upper Helderberg group, near Jamesville, Onondaga county, asso¬ 
ciated with species of Loxonema, Pleurotomaria and of Coleoprion. 
The above association of species is, in many respects, extremely similar to 
that of the cherty beds at Dublin, Ohio. The species of Coleoprion is appar¬ 
ently identical in the two localities; and of the other genera, several of the 
species are closely allied. 
