GASTROPODA. 893 
Bucania crassa. ] 
sides. In the cast the expansion appears very abrupt, but doubtless it is much less 
so in the shell itself. Inner lip slightly reflexed at the sides, thick centrally; outer 
lip broadly and deeply sinuate. Surface markings unknown; slit long. The best 
specimen seen has the following dimensions: entire hight 46 mm.; hight of aperture 
29 mm.; greatest width of same 33 mm.; width and hight of last volution just 
behind the aperture about 23 mm.; hight and width of inner end of same 5 and 8.5 
mm. respectively; greatest diameter of umbilicus about 235 mm.; length of slit 
about 31 mm. 
The hight in this species is relatively greater than in B. frankfortensis, which 
we consider as more closely related than any of the other species. The aperture 
also is less nearly triangular, the apertural margin, as seen in a side view, less 
uniformly curved, the umbilicus larger, and the volutions more evenly rounded on 
the back. The next species, B. crassa, is a more closely coiled and heavier shell, 
having, therefore, also a smaller umbilicus. The form of the mouth and sinus is 
also different. Casts of B. simulatrix resemble those of the associated Salpingostoma 
richmondensis in aremarkable degree. For comparisons see description of that species. 
Formation and locality—Richmond group of the Cincinnati period, Richmond, Indiana. 
Collection.—}. O. Ulrich. 
Bucania crassa, 2. sp. (Ulrich) 
PLATE LXVII, FIGS. 46—48. 
This species, though closely resembling B. frankfortensis and B. nashvillensis in 
many respects, will be distinguished almost at a glance by its uniformly convex 
instead of subangular dorsum. This difference, in conjunction with a greater 
relative width of the whorls, causes the aperture to be proportionally wider. The 
lower lip also, though strong, has a longer slope and its surface is less convex. 
The umbilicus is somewhat smaller and more abrupt than in B. frankfortensis, and 
the shell more globose. 
The specimen figured has suffered considerably from maceration, the slit-band 
and all, excepting the strongest of the surface markings, being quite obliterated. 
On two other specimens, neither as complete as the one illustrated, there is a 
low, yet well defined, rounded dorsal ridge, and in one this is accompanied on each 
side by a faint furrow, while anteriorly it terminates in an open slit about 17 mm. 
long. Whether this dorsal ridge was originally flat or concave on the summit, and 
bore lunulz, we are unable to say. Still, it is to be expected that such a condition 
obtained on the perfect shell. As to the surface markings, what remains of them 
indicates a sculpture similar to that shown in our figures of B. lindsleyi and B. 
nashvillensis. (See plate LXVI.) 
