242 COLUMELLA. 



3. American species. 

 7. Columella edentula (Drap.). PL 30, figs. 12 to 17. 



Description on page 236. In some localities, such as Oswego, 

 Clackamas Co., Oregon, and the Magdalen Islands, Gulf of 

 St. Lawrence, the specimens resemble the typical European 

 edentula closely. Two from Oswego, Ore., measure : 



Length 2.2, diam. 1.35 mm., 6V2 whorls. 



Length 2, diam. 1.3 mm., 5y 2 whorls. 



Generally in America the size, especially the diameter, is 

 noticeably smaller than in the typical form of Europe; and 

 there is some reason for segregating the prevalent form in 

 the eastern states as a local race, simplex Gld. 



Length 2.15, diam. 1.1 mm., 5% whorls. Oxford Co., Maine. 



Length 2.1, diam. 1.15 mm., G 1 /^ whorls. Clementon, N. J. 



Length 1.85, diam. 1.15 mm., 5y 2 whorls. Beaver Co., Pa. 



Length 1.8, diam. 1.1 mm., 5y 2 whorls. Conecuh Co., Ala. 



Most of the specimens in almost any lot collected are im- 

 mature. In some places the full size seems to be rarely if ever 

 attained. Gould's type of simplex, measuring y 1 - inch long, 

 -fa wide, was either immature or from such a dwarf colony. 

 The surface is nearly smooth, showing irregular and very low 

 growth-wrinkles under the microscope. 



This simplex form (pi. 30, figs. 15, 16, 17) is about the size 

 of the Caucasian C. e. nana Bttg., which from the description 

 and figure would hardly be distinguishable from the American 

 form. 



The small simplex form of the species I have seen from the 

 states of Maine, Massachusetts, Rhode Island, New York, New 

 Jersey, Pennsylvania, Wisconsin, Minnesota, Alabama and 

 eastern Canada. 



A few lots appear variable or intermediate between the 

 large and small races. 



In a few places there is a larger form (pi. 30, fig. 14) which 

 agrees with the account of C. e. var. turitella West, in shape, 

 but it has a distinctly striate surface. As the specimens are 

 from several rather widely separated places with diverse 

 faunal associations, I do not give them a special name. 



