862 LAND AND FRESH-WATER SHELLS OF N. A. [PART IV. 



SO by the shouldering of the whorls; body-whorl inflated, suban- 

 gulated a little below the suture, from which angle it shelves towards 

 it, and having two or three dark, broad bands revolving round it; 

 lines of growth curved and very distinct, almost like crowded ribs; 

 fissure perfectly straight, very narrow and not deep ; aperture rather 

 Fig. 6S1. Fig. 685. long, of a dusky color within and ornamented 



by three broad and distinct bands there ; col- 

 umella smooth, except at the lower part, where 

 it is sliglitly thickened. 



Habitat. — Coosa River, Alabama. 

 Length of shell, nine-sixteenths; breadth 

 of shell, three-eighths of an inch. Length of aperture, live-sixteenths ; 

 breadth of aperture, three-sixteenths of an inch. 



Observations. — A short, ovate species resembling in some respects 

 G. ovalis (nobis) herein described ; it is less elevated than that spe- 

 cies, juore ventricose, and its surface is rougher ; indeed, there seem 

 to be some indications of obscui-e folds on the body-whorl of this 

 species near the suture, which in very old specimens may be more 

 fully expressed; and +hus bring it into close affinity with 31. salebrosa 

 (nobis). — Anthony. 



Having compared Mr. Anthony's types of his S. bulbosum 

 and S. ovalis, together with other specimens, I am convinced 

 that they are the extreme forms of one species. Willi regard 

 to the striae of the former being rougher than those of the 

 latter species, some of the specimens of oralis before me 

 have exactly the same striation, disposed somewhat to rise 

 into folds near the suture which distinguishes the typical bul- 

 bosum. JS. salebrosum is a larger and more cylindrical species, 

 and S. bulbosum is more closely allied to S. incisum, Lea. 



The description of S, ovalis follows, and figures of both 

 that and bulbosum are given from Mr. Anthony's types. 



Schizostoma ovalis. — Shell smooth, oval, olivaceous, moderately 

 thick ; spire obtusely elevated, composed of about 5-G convex whorls, 

 of which two are generally lost by truncation; sutures deeply im- 

 pressed; aperture broadly elliptical, banded within; fissure direct, 

 exceedingly narrow and very deep, extending nearly one-half around 

 the shell ; columella slightly curved by a callus. 



Habitat. — Coosa River, Alabama. 



Length of shell, ten-sixteenths ; breadth of shell seven-sixteenths 



