18 



THE NAUTILUS. 



Length 14.00; width 8.50; aperture length 10.00; width 4.00 

 mill. (Rochester, N. Y.) 



Length 13.00; width 8.o0 ; aperture length 10.00; width 4.50 

 mill. (Rochester, N. Y.J 



Length 13.50 ; width 9.00 ; aperture length 10.50 ; widtli 4.50 

 mill. (La Porte, Ind.) 



Length 9.00 ; width 6.00 ; aperture length 6.50 ; width 3.00 

 mill. (Chicago.) 



Animal simiiar to that of gyrina. Jaw and radula in all respects 

 like those of gyrina. Distribution : eastern and southern states 

 from Maine to Georgia and west to Michigan and Illinois; Southern 

 Canada. Geological distribution : Pleistocene ; Loess. Habitat : 

 in ponds and streams, adhering to sticks and stones, and crawling 

 over the muddy bottom. 



Only a single lot of shells has been found which could be referred 

 to this species and that was collected in the drift along the shore of 

 Lake Michigan at Miller's, Indiana. The nearest typical heteros- 

 tropha have been found living in Pine Lake, La Porte Co., Indiana. 

 It is very probable that this species is not found in any abundance 

 west of Indiana, its place being taken by gyrina, sayii and integra. 

 Under distribution above, only those states are given from which 

 the writer has seen authentic specimens. 



Physa Sayil Tappan. Fig. 1. 



Physa sayii Tappan, Amer. Journ. Sci. (1), vol. xxxv, p. 369, 

 pi. iii, tig. 3, 1839. Physa warreniana Lea, Proc. Phil. Acad. 

 Sci., p. 115, 1864. 



Shell polished, ovate, whorl 5-5^ ; spire elevated, very acute, 

 the whorls moderately convex ; color light 

 horn to light chestnut ; sculpture consisting 

 of rather coarse growth lines, crossed by 

 numerous fine, impressed spiral lines, giving 

 the surface of the shell rather a wavy appear- 

 ance, as figured for gyrina; sutures slightly 

 impressed, bordered as in heterostropha ; 

 protoconch consisting of one and a half 

 smooth, glossy whorls of a dark chestnut color ; aperture very large, 

 long oval, three-fourths to four-fifths the length of the whole shell ; 

 peristome thin, generally not much thickened within, whitish some- 

 times bordered with reddish ; columella slightly twisted and cov- 



Fig. 2. 



