112 AMERICAN JOURNAL 



DESCRIPTION OF NEW SPECIES OP PRESH-WATER 

 SHELLS FROM MICHIGAN. 



BY A. 0. CURRIER. 



Physa deformis, Currier. — Plate 6, fig. 1. 



Description. — Shell small, narrowly ovate, thick ; ■whorls 4, 

 ■well rounded, the last not proportionately enlarged, but some- 

 ■what flattened, ■iivhich, in connection -with its ■well-rounded 

 ■whorls, gives the shell a deformed appearance. A broad, thick 

 deposit of callus on the body ■whorl extends to the base of the 

 columellar lip, which is twisted and appressed. 



Length 10, diam. 4 mill. 



Habitat. — Grand Rapids, Michigan. My Cabinet. Cabinet 

 of Academy of Natural Sciences. 



BuLiNus Tryoni, Currier. — Plate 6, fig. 2. 



Description. — Shell cylindrical, smooth, dark horn color ; 

 ■whorls 6, flatly rounded ; aperture one-half the length of shell, 

 pink within ; columella twisted, with a light callus. 



Length 18, diam. 6 mill. 



HaUtat. — Grand Rapids, Mich. My Cabinet. Cabinet of 

 Academy of Natural Sciences. 



Observations. — This shell differs from B. Jtypnorun by its 

 larger size, less attenuated spire, more twisted columella, and its 

 uniform pink aperture. 



Melantho gibba, Currier. — Plate 6, fig. 8. 



Description. — Shell rhombic, imperforate, rather thick, some- 

 what roughened by lines of growth ; epidermis greenish brown : 

 whorls 5, well rounded, the last subangulate ; aperture rhombic, 

 half the length of shell, tinged with rufous within ; columella 

 white, thickened by a callus which extends across the parietal 

 wall of the aperture. 



