THK NAUTILUS. II 



spire and aperture of equal length, to the long, spiral reflexa. In 

 this lot one may trace the variation from iowaensis, through umbrosa 

 and jolietensis to typical rejlexa. 



In a lot of shells received from Mr. Henry Hemphill, four speci- 

 mens were found which appear to belong here. Two specimens are 

 fairly typical, while two sliow a variation toward variety umbrosa. 

 They are from Tiake Albert Lea, Minnesota. The types are from 

 Muscatine, Iowa. 



Limnsea rejlexa crystalensis nov. var. 



Shell solid, with dome-shaped spire ; whorls 5-6, flatly rounded, 

 loosely coiled; sutures not impressed, but well marked; spire 

 of variable length, but typically about the length of the aper- 

 ture; aperture long-ovate, peristome with a heavy internal rib; 

 columellar callus heavy, spreading over the inner lip and crossed by 

 a strong plait ; umbilical region showing a slight perforation beneath 

 the overhanging columellar callus ; color liglit or dark horn, some 

 species are strongly zebra-marked, and all exhibit the fine wavy 

 sculpture of this group of Limnjeas. It seems sometimes malleated. 



Length 19..50, width 8.00, aperture length 9.00, width 4.00 mill. 



Length 21.00, width 8.00, aperture length 10.00, width 5.00 mill. 



Length 22.00, width 9.00, aperture length 10.50, width 5.50 mill. 



Length 23.00, width 8.50, aperture length 10.50, width 5.00 mill. 



Length 23.50, width 1 0.50^ aperture length 12.50, width 5.50 mill. 



Length 28.00, width 10.00, aperture length 12.00, width G.OO mill. 



Length 23.50, width 9.00, aperture length 11. 00, width 5.00 mill. 



Length 28.00, width 9.00, aperture length 11.50, width 5.50 mill. 



This variety may be collected in countless numbers at Crystal 

 Lake, Illinois. The lot from which this description was drawn num- 

 bers 105 specimens, and was collected by Dr. N. H. Lyon. This 

 variety bears the same relation to rejlexa that variety michiganensis 

 Walker does \o paluslris^and its growth is probably governed by the 

 same piiysical conditions. 



Limnsea rejlexa hemphilliana nov. var. 



Shell i-ather solid ; color liglit horn ; whorls G, very fiat-sided, 

 loosely coiled, nuclear whorls very dark red; sutures not impressed ; 

 spire acutely pyramidal, about as long as the aperture ; aperture 

 elongate-ovate ; peristome thin, bordered internally by a red band ; 



