CALL ON NEW MOLLUSCA. 7 



ery, above which it is flattened, many-banded and smooth, or bandless 

 and coarsely multistriate, the striae cord-like and variable in number, 

 coarsely and obliquely wrinkled by the well-marked lines of growth; 

 suture well but irregularly impressed; aperture oblique, trapezoidal, 

 twice as long as broad, effuse, white or creamy-white within, often 

 banded with broad purple bands, slightly retuse at columellar region; 

 peristome simple, sigmoid, a little thickened, somewhat reflexed at 

 base of columella; columella thickened, always white, twisted; parietal 

 wall usually with a thick deposit of callus, which is sensibly thickened 

 near the posterior angle of aperture. 



Operculum black, otherwise as usual in the genus. 



Habitat and Station. — This shell occurred only in a limited area in 

 Dyke's Creek, a clear and cold mountain stream tributary to the Etowah 

 River, Floyd County, Georgia. Associated with it were numerous speci- 

 mens of Margaritana georgiana Lea, two species of undetermined Unio, 

 Goniobasis vittata Anthony, and Goniobasis bella Conrad. It has the 

 habit of Anculosa, and is to be sought only in the most swiftly flowing 

 and deepest portions of the stream, on rocks. It is not abundant, the 

 most painstaking examination revealing some two hundred individuals. 



The characters given are those which appear to be most constant, 

 though some of these are variable. The variations, as usual in this 

 family, range through wide limits. Thus, occasional specimens of the 

 smooth and banded type depart so far from the figure that the whorls 

 are loosely coiled and very much rounded; this does not appear to be 

 of varietal value, but is pathologic. The color, again, ranges from light 

 yellow to dark olive, and the peripheral angle becomes almost a carina. 

 The average dimensions of seventeen individuals are, for length, 2 1 . 1 4 ,nm ; 

 for breadth, i2.o2 mrn . The largest specimen has a length of 26.o8 mm 

 and a diameter of 14.00'"'". 



Specimens may be seen in the United States National Museum, 

 Cornell University, New York State Museum of Natural History, 

 Amherst College, Davenport Academy of Natural Sciences, and in the 

 private collections of C. E. Beecher, T. H. Aldrich, and the writer. 

 The species is named in honor of Dr. R. E. C. Stearns, so well known 

 for his researches on the Pacific Coast mollusca. 



