THE NAUTILUS. 103 



Bulimulus lamellifer n. sp. 



General form of A. spirifer ; waxen white or light brownish ; the 

 surface more or less granulose, as in examples of B. spirifer. Whorls 

 about 65. Aperture over half the altitude usually, but sometimes 

 less than half; the lip-ends conspicuously approaching, joined by a 

 short callus ; peristome broadly expanded and reflexed, much as in 

 spirifer. Columella showing from the aperture a sharp, oblique lam- 

 ina; this lamina becoming very high internally, projecting in a 

 square or bisinuate plate. The type measures, alt. 32, diam. 15 

 mm. ; but they are very variable in size, the smallest seen being 

 23J rnm. long. The square or emargiuate internal plate differs con- 

 spicuously from the corkscrew twisted fold of B. spirifer, and is ap- 

 parently a constant character. Seventeen specimens examined. 



Lower California (W. M. Gabb). 



These forms are evidently different from B. spirifer Gabb, B. 

 bryanti Cooper and B. veseyanus Dall, the species of this group de- 

 scribed by American naturalists. A careful comparison with the 

 descriptions of B. lapidivagus, dentifer, subspirifer aud dismenicus of 

 Mabille, causes me to consider these also as specifically distinct from 

 the forms described above. Illustrations will appear in the next 

 number of the Manual of Conchologi/, in which the other North 

 American Bulimuli will also be figured. 



NEW AMERICAN UNIONID.E. 



BY WM. A. MARSH, ALEDO, MERCER CO., ILL. 



TJnio superiorensis n. sp. 



Shell smooth, obovate, slightly inflated, inequilateral, rounded 

 before, oblique, obtusely angular behind, with or without rays, rays 

 when present interrupted by lines of growth. Substance of shell 

 thick, beaks small, with a few rather coarse undulations; umbonial 

 slope flattened, ligament long, dark brown ; epidermis dark olive ; 

 growth lines very close, quite prominent, cardinal teeth large and 

 solid, compressed and nearly smooth, double in left valve and widely 

 separated ; lateral teeth long, thick and nearly straight, anterior 

 cicatrices deep and rounded, posterior cicatrices confluent and well 

 impressed. Cavity of shell deep ; cavity of beaks deep and rounded ; 

 nacre white, sometimes shining. 



Habitat: Michipicoton River, upper shore of Lake Superior, 

 Canada. 



