MOLLUSCA OF MICHIGAN— WALKER. 5:3 



Pupa exigua, Sav, Jour. A. N. S. P., II., 375,(1822). 



Carychium exiguum, W. G. Binnev, L. & F. W. Shells, II., 6, fig. 8, (1865). 



, Miles, Rep. Geol. Siirv. Mich., 236, (1861). 



-^ , Currier, Shell-bearing Moll. Mich. p. 6, (1868). 



, DeCamp, Shell-bearing Moll. Mich., 7, (1881). 



■ , Walker, Rev. Moll. Fauna Mich., 17, (1894). 



This minute, slender, white species is semi-amphibious in its habits, and 

 has a general distribution over the entire state. Distinguished from C. exile, 

 by its shorter, more inflated shape and nearly smooth surface. The larger 

 examples noted above are analogous to the var. canadense of C. exile, but 

 they are more discontinuous in their range and seem rather to be the effect 

 of specially favorable conditions of environment rather than a true race. 



CARYCHIUn EXILE H. C. Lea. 



Shell minute, elongated, cyhndrical, apex obtuse, 

 white, transparent, shining; whorls 5-5^, somewhat 

 shouldered, closely, • regularly and distinctly striate; 

 suture deeply impressed; aperture small; very 

 oblique, about one-third the length of the shells; 

 outer hp reflected, more or less thickened; colu- 

 mellar having an obtuse fold below and a promi- 

 nent entering fold above. 



Alt. 1.75, diam. .6 mm. 



Fig. 167. C. exile. (Clapp.) X20, 



Carychium exile, H. C. Lea, Am. J. Sc. (1), XLIL, 109, pi. I., fig. 5, (1841). 

 , Walker, Rev. Moll. Fauna Mich., 17, (1894). 



Var. CANADENSE Clapp. 



L^niformly larger. 



Alt. 2.1, diam. .75 mm. 



Carychium exile canadense, Clapp, Naut. 

 XIX., 138, pi. VIIL, figs. 1, 2, 6 and 7, (1906). 



This species is easily separated from C. 

 exiguum by its more slender, elongated shell, 

 which is distinctly striate. The typical form 

 is apparently rarely found in the southern 

 part of the state, having been recognized only 

 from Saginaw and Shelby, Macomb county. 

 The variety is characteristic of northern part 

 of the state where it ranges from Roscommon 

 countv northerly through the entire upper 



Fig. 168. C. exile^canadense. iCl^p^.) ^^^.^^^^^ 

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