1889.] 
289 
Foerste. 
Cyrtolites Yodngi, sp. nov. 
(plate yi, fig. 7.) 
The single specimen at hand from Hanover, Indiana, presents 
marked characteristics distinguishing the same from any species 
of this series of rocks. It is composed of three to three and a half 
whorls or coils, the outer continually embracing the inner, leav- 
ing the latter however exposed on each side thus giving rise to 
a shallow umbilicus on either side of the shell. The shell is very 
much compressed laterally, the sides meeting under very acute an- 
gles forming a sharp keel. The surface of the shell is ornamented 
by fine not very distinct striae, visible under a lens, which bend 
backwards towards the keel. The specimen has a longest diam- 
eter of 6.8 mm., a shortest diameter, vertical to the last of 5.8 mm., 
and a width near the aperture of 1 mm. 
Pleurotomaria labrosa, var. occidens, Hall. 
(PLATE V, FIG. 14.) 
Specimens of the following description are common at Collins- 
ville, Alabama. Shell with the spire moderately elevated ; com- 
posed of three volutions, with occasionally a part of a fourth 
volution ; the last one rapidly expanding, subangular, the angle 
formed by the slit band which is situated a little above the middle 
of the volution. The shell above the slit band is somewhat flat- 
tened ; below this band the shell is rounded, or even ventricose 
towards the mouth. At the mouth the shell below the slit band 
descends almost perpendicularly for some distance before it curves 
inwardly towards and into the umbilicus. The slit band is usually 
a groove defined above and below by strong revolving striae and 
ornamented by transverse striae which in the groove have a lunar 
form, the concave side being directed towards the mouth. 
In one of our specimens the slit band, for some reason, has been 
reversed so as to form a raised, flattened ridge, bordered on each 
side by a moderate groove, instead of a well marked groove bor- 
dered by raised striae. The remainder of the shell, both above and 
below the slit band, is ornamented by revolving and transverse 
striae, the former being usually much stronger. 
The largest specimens are 42 mm. in diameter horizontally. A 
smaller, but quite typical specimen, is 29 mm. in diameter liorizon- 
FROCEEDINGS B. S. N. H. VOL. XXIV 19 DECEMBER, 1889. 
