22 THE NAUTILUS. 



blue tree snails of the southwest coast, I obtained several of 

 them from residents of Chokoloskee. These were Oxystyla 

 floridensis pure and simple, and they had been boiled in water 

 containing a little indigo. We made a number of specimens 

 of this new species aboard the boat in the same way and they 

 were just as nice as those sold by the natives. This receipt is 

 absolutely free to anyone desiring to make new species. 



NEW FORMS OT PLEISTOCENE MOLLUSKS FROM ILLINOIS. 



BY FRANK C. BAKER.* 



A recent examination of Pleistocene material from Grundy 

 County, Illinois, submitted by Mr. Harold E. Culver, of the 

 Illinois State Geological Survey, reveals several new forms 

 of mollusks which seem to need recognition. Upwards of 

 twenty species and varieties occur in the marl deposit, which 

 is post- Wisconsin in age. 



AMNICOLA LUBTRICA GELIDA n. var. 



Shell differing from lustrica in being narrower, with more 

 convex whorls, more deeply impressed sutures, a smaller, 

 rounder aperture, the lip of which is usually thickened 

 within. There are six full whorls in adult individuals. 



Length, 4.25 ; diameter, 2.25 ; aperture length, 1.25 ; width, 

 1.0 mm. Topotype, Collection Museum of Natural History, 

 U. of I., No. P926. 



Length, 4.50; diameter, 2.30; aperture length, 1.40; width, 

 1.0 mm. Paratype. Museum No. P927. 



Length, 4.0; diameter, 2.50; aperture length, 1.50; width, 

 1.10 mm. Paratype. Museum No. P927. 



Types from near Morris, Grundy County, Illinois, in marl 

 deposit. 



This small Amnicola is one of the most abundant species 

 in Pleistocene deposits, and seems to be widely distributed, 



* Contribution from the Museum of Natural History, University of 

 Illinois, No. 16. 



