102 
THE NAUTILUS. 
NEW FORMS OF AMERICAN SHELLS. 
BY II. A. PILSBRY. 
Gastrodonta (Pseudohyalina) lateumbilicata n. sp. 
Shell resembling Ps. limatula in color, texture and sculpture, but 
much depressed, the upper surface almost flat, last whorl of much 
smaller calibre, the umbilicus very much wider, shallow, its cavity 
widely open and saucer-shaped, much as in Helicodiscus lineatus. 
Alt. P4, diam. 4 - 3 mm. 
Hab., near Woodville, Alabama. Coll, by H. E. Sargent, whose 
labors in northern Alabama have been remarkably fruitful in 
increasing our knowledge of the conchology and mammalogy of 
Alabama, as well as in his chosen work as an educator. 
Somatogyrus Sargenti n. sp. 
About the size of S. aureus Tryon, but shouldered as in S. sub- 
globosus Say, and imperforate. Shell globose-turbinate, light olive- 
green, smooth except for fine growth lines. Whorls about 41, those 
of the spire very convex and separated by deep sutures ; last whorl 
shouldered above, flattened toward the suture, large and convex. 
Aperture large, ovate, a little flattened on the parietal side, broadly 
rounded below, narrowly rounded above, and angular at the upper 
insertion of the lip. Columella concave, moderately heavy, the 
callus becoming wider at the umbilical region ; parietal wall with 
a transparent callus layer. Alt. 6, diam. 5 mm. Mud Creek, a 
tributary of the Tennessee K., Ala.; coll, by Prof. H. E. Sargent. 
This species differs from S. integer and the closely allied species 
or varieties depressus, aureus and parvulus in its shouldered whorls, 
planulate below the suture. It has no such heavy columellar callus 
as 8. curriericuius; and it is a smaller species than S. subglobosus 
(isogonus) of Say, with wholly closed umbilicus and differently 
formed columella. 
RANGIA THE PROPER NAME OF THE MACTROID GENUS GNATHODON. 
BY THEODORE GILL. 
Mr. Dali, in the Nautilus (VIII, 27) and Proc. U. S. Nat. 
Mus., (XVII, 91), has shown that the generic name Gnathodon was 
