MEDINAN, NIAGARAN, AND CHESTER FOSSILS 
115 
No glabellae accompany these pygidia belonging to the type 
series. I am unable to discriminate between the glabellae of 
Cyphaspis, Proetus, and Calymene in specimens of such small size, 
but regard Cyphaspis as a possibility in the case of the pygidia 
here described. 
I. A NEW GASTEROPOD FROM THE GUELPH FORMATION OF OHIO 
Straparollus paveyi Sp. nov. 
Plate XV, figs. 1 A, B, C 
Shell strongly depressed; greatest lateral diameter 63 mm.; 
height 37 mm. The spire rises about 20 mm. above the last 
volution at its aperture. Volutions at least 5, possibly 6. The 
suture between the last volution and that immediatel}^ preceding 
is about two-fifths of the height of the latter above its base. 
From this suture downward for a short distance the upper part 
of the inner outline of the cross-section of the last volution is 
distinctly though moderately concave. Along the remainder 
of its contour this outline is approximately circular, but slightly 
depressed vertically, and with a tendency toward oblique flatten- 
ing of that part of its slope which is immediately above mid-height 
of the last volution. Near the aperture, the lateral diameter of 
the last volution is 23.5 mm., and its vertical diameter is 22 mm. 
The oblique flattening above mid-height forms an angle of about 
30° with the vertical axis of the shell. The umbilicus is wide 
and open, showing all of the volutions; its greatest diameter in 
the specimen here described is 20 mm. 
Owing to the oblique flattening of that part of the last volution 
which is immediately above mid-height there is a tendency toward 
a shoulder aboutf three-fifths of the distance between mid-height 
and the suture above. From the suture as far as the middle of 
the obliquely flattened slope, the transverse striae curve back- 
ward at an angle of about 80° with the suture. From this point 
the striae curve more strongly backward, at an angle of 60° with 
the horizontal, until about 3 mm. below mid-height of the volu- 
tion, .beyond which they curve forward until they assume a radial 
direction along the lower face of the volution. There is a tend- 
