150 PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. i 



only two specimens in the collection have the outer lip fractured, and I \ 



am therefore unable to pronounce conclusively upon the presence of a 



true uot<;h. 



Pleurotoma venusta, n. sp. 



Plate, fig. 2. 



Slender, acuminate ; whorls about nine, convex, ornamented by numer- 

 ous fine revolving lines, which on the body-whorl are disposed in pairs; 

 one deeply' impressed line margins the majority of the volutions imme- 

 diately below the suture ; sin nated lines of growth not prominent; si)ire 

 and aperture of about equal length. 



Lengtl), l-l inch. (No. 1509.) 



Jackson, Miss. 



Pleurotoma platysoma, n. sp. 



Plate, fig. 3. 



Whorls ? in number, flattened, each volution following the other al- 

 most in direct continuation without any prominent sutural division, and 

 ornamented with numerous revolving lines, which on the caudal portion 

 of the body whorl tend to alternate, a fine line interposing itself between 

 the more prominent ones ; ajjerture. probably a little more than one-third 

 the length of the entire shell ; notch deep, sigmoidal. 



Length, 2 inches ? (No. 891C.) 



Atascosa County, Texas. 



EUCHEILODON, Gabb. 



EUCHEILODON CRENO-CARINATA, n. Sp. 



Plate, fig. 4. 



Whorls subscalariform, flattened above, the angulation formed by a 

 doubly crenulated carina; volutions ornamented by numerous revolving, 

 profoundly elevated stri^, which are decussated by the much finer sinu- 

 ated lines of growth ; the upper or flattened portion with a prominent 

 beaded line bordering the suture, and two (a finer and a coarser line) 

 intermediate ones between the same and the carina; outer lip grooved 

 within, and probably sharply crenulated by the terminations of the re- 

 volving striiie; columella with about eleven beads, which decrease in 

 size from above downwards. Aperture nearly equal in length to the 

 spire? 



Length of fragment, 1 inch. (No. 8921.) 



Jackson, Miss. 



SCALARIA, Lam. 



SCALARIA UNILINEATA, U. Sp. 



Plate, fig. 5. 



Whorls about nine in number, convex, with numerous very faint, 

 almost invisible, revolving lines, and much more ijrominent transverse 



