140 Trans. Acad. Sci. of St. Louis. 
usually not nodulated by the lines of interrupted growth, 
which are more apt to appear only between them, so that the 
peculiar tessellated sculpture of Scobinella is wanting or 
much less developed. There are apparently three known 
species which may be identified by the following charac- 
ters : — 
Shoulder angle of the whorls obtusely rounded and situated far above the 
middle; spiral lyrae coarse and ClOS€-SCt.. cece receesceceee S500 3600 73 
Shoulder angle broadly angulate in profile and situated only just visibly 
above the middle; spiral lyrae finer and unequally spaced.....-......+- 3 
2— Shell stouter, the lyrae very coarse and somewhat dissected by the lines 
of interrupted growth, especially on and above the shoulder, giving a 
granular effect; shoulder angle more prominent and bicarinate. Jack- 
SONIAN MOCEHEL eee vote oe cree icieahetscine eieie whats crenocarinatum Heilp. 
Shell much smaller and more slender, the spiral lyrae not quite so coarse, 
flat and very clearly defined throughout, not at all dissected by the lines 
of growth which are only visible in the depressed intervals; shoulder 
angle evenly rounded. Lower Claiborne Eocene of Texas (= laeviplica- 
TUM GADD) .- 20 weeeccccne race ccce cece scvcce secersoee reticulatum Gabb 
3 — Surface of the spire whorls evenly declivous from the finely unicari- 
nate periphery posteriorly to the fine subsutural carina, and, anteriorly 
to the suture, the posterior declivous surface witha fine thread near the 
peripheral carina and another one-third the distance from this thread 
to the subsutural carina, the anterior declivous surface with two fine 
carinae one-fourth and three-fifths the distance from the peripheral 
carina to the suture; body whorl below the posterior end of the 
aperture becoming abruptly closely lyrate; columellar folds numerous 
but very fine and feeble, the posterior isolated fold small though ab- 
ruptly denticuliform. Length of aspecimen having between 2 and 3 body 
whorls,10 mm. Lower Claiborne Eocene of Texas...gabbianum n. sp. 
The type of gabbianum is a unique specimen in the cabinet 
of Mr. T. H. Aldrich. There are apparently two species in the 
Jacksonian Eocene confused under the name crenocarinatum, 
but I am not prepared to define them at present. 
Glyptotoma n. gen. 
Some peculiar small species generally of robust form, hav- 
ing a narrow tumid columella ridge, which is stongly bi- or 
triplicate and the anal sinus median in position and formed 
upon a broad double nodose spiral, require separation as a 
distinct genus for which I would propose the above name. 
The general type of tessellated ornamentation is strikingly 
