GASTROPODA. 887 
Bucania minnesotensis.] 
One seems to show obscure traces of very fine spiral lines between the stronger 
ones, and it is possible that such lines will be found on the perfect shell. 
B. halli is closely related to B. sulcatina, but that species has wider volutions, 
and, although they do not enlarge any more rapidly, the proportional width of the 
aperture is greater, being quite equal to the hight of the shell, which is not the case 
in the present species. The whole form of that shell is also more globose. B, intexta 
is a smaller and narrower shell, and has more closely arranged revolving ribs and 
less depressed volutions. 
We have four fragmentary casts of the interior, collected in the Fusispira bed 
of Goodhue and Fillmore counties, that may belong to this species. 
Formation and locality.—Stones River group, Cannon Falls, Minnesota (six specimens); Black River 
group, Mercer county, Kentucky (eight specimens). 
Collections.—E. O. Ulrich; W. H. Scofield. 
BUcANIA MINNESOTENSIS, 7. Sp. 
PLATE LXVI, FIGS. 9 and 10. 
This is associated with and probably closely related to B. halli. Still there 
should be no difficulty in distinguishing the two forms since this grows to much 
greater size and yet has the same number of volutions. The last whorl especially 
enlarges rapidly, though relatively more in hight than in width. The sutures are 
deeper and the slope of the umbilicus, taken as a whole, is not so flat. Still the 
flatness of the slope increases with growth until on the last third of the outer whorl 
it has become decidedly concave; causing the sutural portion to appear swollen. 
The surface markings seem to be about the same in the two species. 
Formation and locality—Vanuxemia bed of the Stones River group, Goodhue county, Minnesota. 
Collection.—H. O. Ulrich. 
BucaNIA EMMONSI, . sp. 
PLATE LXVI, FIGS. 1—3. 
This species differs from B. halli, which it resembles closely, in being smaller 
and in having on the whole narrower yet more speading volutions. The volutions 
are more rounded in the umbilicus, causing the suture line to be deeper. The latter 
is peculiar in being deepened at regular intervals by the development of short, 
wave-like dents in the ventral side of the volutions. Similar dents are to be seen 
also on the sides of the volution in the Fountain specimens, but they cannot be seen 
on the even better preserved Tennessee shell. These sutural indentations dis- 
tinguish the species not only from B. halli but from the even nearer B. intexta and 
all the other species now known of the genus. In a specimen 18 mm, high, the 
