gasteropoda. 
119 
is no evidence Avhatever of such strise. I do not, however, at present find 
any sufficient reason for separating them from those figured on plate 24, in 
which the posterior part of the last volution is distinctly tricarinate. 
Bellerophon IVLera. 
PLATE XXV, FIGS. 9-14 ; AND PLATE XXVI, FIGS. 19-24. 
Bellerophon Mara, Hall. Illustrations of Devonian Fossils : Gasteropoda, pi. 22. 1876. 
“ Neleus, H.&W. Illustrations of Devonian Fossils: Gasteropoda, pi. 22. 1876. 
Not “ “ “ Geol. Rep. U. S. Survey, 40th Parallel: Clarence King, Geologist (in MS.). 
Shell subglobose, or broadly subovoid; length about equal to the greatest 
width at the aperture ; in imperfect specimens the width is usually greater 
than the length. Inner volutions small and gradually enlarging to the 
third, which is more rapidly expanded, the exposed portion of the outer 
one being extremely ventricose. Aperture greatly expanded, the peris¬ 
tome broadly sinuate in front and auriculate at the sides; somewhat 
thickened and repand as it approaches the umbilicus, over which it 
extends, continuing in a thickened callosity across the columellar side. 
The dorsum is marked by a distinct carina and the entire surface by strong 
pustulose striae, or rows of pustules, which are arranged along lines parallel 
to the striae of growth. The dorsal carina is also pustulose. These markings 
are somewhat less conspicuous on the anterior and lateral margins of the 
shell. 
This fossil, when entire, presents a strong rotund form until near the aper¬ 
ture, where it becomes abruptly expanded. The shell is thick, and the surface 
completely studded with rows of pustules which, in one direction, are arranged 
in series parallel to the lines of growth in the shell, and, in the other direction, 
in diagonal lines crossing these, giving the aspect of a quincunx arrangement. 
On the removal of the shell the carina on the cast usually extends but a short 
distance from the margin of the aperture, and the dorsum beyond this is 
obtusely or obscurely angular. In a few examples, which present no marks of 
specific distinction, the carinate dorsum is continuous for the entire extent of the 
