426 THE CHICAGO ACADEMY OF SCIENCES. 



many specimens have, in addition to the spiral impressed lines, a num- 

 ber of heavy, more or less equidistant spiral ridges encircling the body 

 whorl; the last whorl may also be somewhat malleated; whorls 5 to 

 oy 2) globose, roundly shouldered, inflated, the body whorl very globose 

 and disproportionately swollen; spire varying from broadly acute to 

 depressed, usually about half the length of the entire shell; suture 

 well marked, often deeply impressed; aperture roundly-ovate, rarely 

 quadrate, seldom flaring; peristome with internal, varical thickening; 

 inner lip wide, whitish, broadly reflected over the umbilical region 

 producing a wide, flat expansion, which emarginates the umbilical 

 chink, as in the typical form; umbilical chink usually very large and 

 conspicuous ; imperforate individuals are rare ; the parietal callus is 

 thick and wide producing a continuous aperture in some specimens ; 

 the lower part of the aperture is somewhat effuse in a few individuals. 



Length. 



Breadth. 



Aperture length. 



Breadth. 



23.50 



15.00 



13.00 





7.50 mill. 



22.00 



15.00 



12.00 





8.00 " 



24.00 



16.00 



13.50 





9.00 " 



24.00 



16.25 



13.00 





8.00 " 



26.50 



19.50 



16.50 





11.00 " 



25.00 



19.00 



16.00 





10.00 " 



26.00 



19.00 



16.50 





10.00 " 



Types : The Chicago Academy of Sciences, 19 specimens, No. 

 24504; cotypes, coll. Bryant Walker, Detroit, Mich. ; Academy of 

 Natural Sciences, Philadelphia. 



Type Locality : East shore Tomahawk Lake, Oneida Co., Wis. 



Animal : Similar to typical emarginata. The animals of the 

 Tomahawk Lake race are of two very pronounced colors, black with 

 white dots and bright yellow with white dots. This difference in the 

 animal is quite conspicuous rendering the light colored specimens less 

 noticeable than the dark colored individuals against the white sand 

 of the shore. 



Jaw, Radula and Genitalia: In all respects similar to those of 

 emarginata. 



Range: (Figure 46). Wisconsin. 



Wisconsinensis has been only seen from the type locality. It 

 doubtless lives in many lakes in Northern Wisconsin, and has probably 

 been identified as mighelsi. 



RECORDS. 1 



Wisconsin.: Tomahawk Lake, Oneida Co. (Baker). 



J The statement in the Nautilus vol. XXIV, p. 28, in which certain speci- 

 mens from Brome Lake are referred to this race is erroneous. A series re- 

 cently received from Mr. Latchford shows them to be referable to mighelsi. 



