892 THE PALEONTOLOGY OF MINNESOTA. 
[Bucania micronema. 
showing that the aperture is relatively larger in adult examples. The small 
specimen, which is one of several, was at first believed to be distinct, but a careful 
comparison of the whole series resulted in the conviction that the small examples 
were merely immature. 
Formation and localitykx—Upper part of Trenton group, Mercer and Boyle counties, Kentucky. 
Collection.—E. O. Ulrich. 
Bucania MicRoNEMA, ”. sp. (Ulrich.) 
PLATE LXVI, FIGS. 26—29. 
Of this form we have but a single example. Although closely resembling B. 
sublata, B. lindsleyi and B. rugatina, in one or another feature, we are fully persuaded 
of its specific distinctness. The specimen, which has the appearance of being 
mature, is so much smaller than the second of the species mentioned that further 
comparisons with it are probably unnecessary. As to B. sublata, the present shell 
has it volutions narrowly rounded on the sides instead of sharply angular, its aper- 
ture is relatively larger, and its surface markings, which are not visible to the 
unassisted eye, are much finer. Compared with Bb. rugatina, with which it was 
found, its volutions expand more rapidly, giving a wider aperture, and its surface 
markings are much finer. Besides the transverse lines are much less distinct and 
not wave-like, while the lines running in the opposite direction, of which there are 
about five instead of two in 1 mm., are not only finer but more continuous, appearing 
like irregular wavy, knotted lines, running obliquely forward from the umbilicus to 
the slit-band. 
Formation and locality.—Near top of Trenton group, Danville, Kentucky. 
Collection.—K. O. Ulrich. 
BucanNIa SIMULATRIX, n. sp. (Ulrich.) 
PLATE LXIII, FIGS. 48 and 49; PLATE LXVII, FIG. 45. 
Shell large, known from casts of the interior only. These consist of three or 
four comparatively slender and loosely coiled volutions, leaving a large umbilicus 
in which all the inner whorls are clearly exposed. Volutions somewhat reniform 
in section, narrowly rounded in the ventral third of the sides, the ventral surface 
gently concave, the dorsal part of the section nearly semi-circular. Last volution 
obtusely carinated, with the dorso-ventral diameter increasing toward the aperture 
more rapidly than is the case with the inner volutions, the hight and width of the 
whorl just behind the aperture being about equal, while at the smaller end the two 
dimensions are respectively about as three is to five. Aperture somewhat triangu- 
lar-ovate, wide below, the expansion taking place chiefly at the lower part of the 
