140 Trans. Acad. Sci. of St. Louis. 



usually not nodulated by the liues 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 close-set 2 



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 Eocene crenocarinatuin 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 Gabb) reticulatum Gabb 



3 — Surface of the spire whorls evenly declirous from the finely unicari- 

 nate periphery posteriorly to the fine subsutural carina, and, anteriorly 

 to the suture, the posterior declivous surface with a 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 a specimen having between 2 and 3 body 

 whorls, 10 mm. Lower Claiborne Eocene of Texas., .gabbiaiiuni n. sp. 



The type of gahhianum 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. 



Gljptotouia n. gen. 



S )me 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 



