160.8 Trans. Acad. Sci. of St. Louis. 
subsutural lyra, two others similar to the subsutural and moderately 
approximate at the middle and another similar lyra between the lower- 
most of the median and the lyra forming the lower margin; spiral 
space below the subsutural lyra exactly equal to the space between 
the lowermost of the median lyrae and the one next below the latter. 
Length of a specimen of about 9 body whorls, 15.5 mm.; width, 3.9 
mm. Lisbon bed, Alabama — Mr. Aldrich...........0.,. strigosa n. sp. 
Strigosa is represented before me by a single specimen in 
rather imperfect condition, but it is a very distinct species 
readily recognizable by the characters of the table. The 
spire whorls are more inflated in eximéa than in either stri- 
gosa or texana, being arcuate in profile; the sides in those 
species are nearly straight. 
Hemisurcula n. gen. 
In this genus the shell is fusiform, with the embryo con- 
oidal, multispiral and closely coiled, the nepionie spire whorls 
alone costate and having also an elevated collar below the 
suture. The more recent whorls become devoid of lyrae or 
costae, though having throughout densely close-set and sub- 
equal microscopic striae, except the body whorl abruptly 
below the posterior end of the aperture, which is obliquely and 
rather coarsely lyrate. The canal is moderate, straight, and, 
together with the aperture, forms about half the length of 
the shell. The sinus is broadly rounded and median in 
position on the spire whorls, the columella simple. The type 
of this genus is Pl. silicata, of Aldrich, a very remarkable 
and isolated species occurring in the Lignitic Eocene of the 
Grege’s Landing beds of Alabama. The beaded subsutural 
collar, subjacent depression and swollen and finely ribbed 
lower parts of the two whorls immediately below the embryo 
are lost completely on the larger whorls, though the 
subsutural collar can be feebly traced as a slightly tumid 
line gradually descending further below the suture with 
the growth of the shell. Besides szlicata, the genus will 
include the much stouter P/. roscoet Harris, from the same 
horizon. 
