Casey — Notes on the Pleurotomidae. 145 
remainder of the shell in gabdi, which is assumed as the type. 
The species before me may be distinguished by the following 
characters : — 
Columella straight and unmodified; embryo very large........... as catenaiels 2 
Columella with a stout plica at about the middle of the aperture proper; 
embryo much smaller, though of the same general] type............+. 3 
2—Embryo stout; subsutural collar flat, composed of two, and, subse- 
quently, about three, coarser spiral carinules; concavity below the 
subsutural collar, long, concave; periphery anterior in position, 
rounded in profile, moderately swollen, with the spiral lines larger. 
Lower Claiborne of Wheelock, Texas.......0.ee2seee ceceee gabbi Con. 
Embryo large but much narrower, the lower whorls similarly, though more 
coarsely, costulate, the upper smooth whorls forming a much more 
acutely elevated apex; subsutural surface broadly, feebly swollen and 
covered with numerous fine but strong carinules merging gradually 
into the small threads of the subjacent concavity; remaining charac- 
ters nearly as in gabbi, the beak more rapidly tapering, very slender at 
tip, the aperture and canal together but little longer than the remain- 
der of the shell. Length of a specimen of 5 body whorls, 23.5 mm.; 
width, 6.8 mm. Lower Claiborne Eocene of Smithville, Texas — 
MPs ALGTICH. canes cctickeiswnjn heels rican 3% <0, < 0's os =tORUMIFOSiris’ i. Sp: 
3 — Form nearly as in the two preceding, the embryo very much smaller in 
size, conical, with the lower whofls ribbed; subsequent whorls each 
with a strongly and abruptly elevated double carina at basal third, the 
two carinae becoming more widely separated and with an intermediate 
thread on the larger whorls; space between the double carina and the 
subsutural cariniform collar broadly concave and with strong and widely 
spaced spiral threads; double carina of the first two body whorls 
crenulate. Lower Claiborne Eocene of Wheelock, Texas — [ Borso- 
Ch oh eosc Sone ae Ba afte his ereatelsiaio! etc dimiel simatic leis siebicieiaie plenta H. & A. 
The last of these species may possibly be subgenerically 
different from the others but certainly cannot be further 
removed. The species figured by Harris as the young of 
plenta is probably specifically different. 
Eosurcula 2. gen. ( 
The embryo in Hosurcula is much narrower than in Pro- 
tosurcula, strongly elevated and smooth throughout, the sub- 
sutural collar smaller and less developed, the fasciolar surface 
thence obliquely ascending but straight in profile or nearly so 
to the obtusely angulate periphery, on and below which the 
spirals become coarser. The aperture and canal are nearly as 
