LYMNEIDA OF NORTH AMERICA. 399 
RANGE: (Figure 43). States bordering Lake Michigan. A species 
of the Canadian region and of the humid division of the Transition 
and Upper Austral life zones. It is apparently a species confined for 
the most part to Lake Michigan; there is but one record (Lake 
Geneva, Wisconsin) away from Lake Michigan and it is possible that 
this record is due to a mixing of labels. 
RECORDS. 
Ittinots: Lake shore, Ravinia, Lake Co. (Baker); Lake Michigan, Oak 
Street, Chicago, Cook Co. (Lyon; Woodruff); lake shore, Lincoln Park, Chi- 
cago (Jensen; Walcott); Lake Michigan, Chicago (Nason); Evanston, Cook 
County (C. S. Raddin); Lake Michigan south of Graceland Avenue, Chicago 
(Walcott). 
INDIANA: Lake Michigan, Millers, Lake Co. (Baker; Woodruff); Lake 
Michigan, Michigan City, La Porte Co. (Daniels). 
MicuicAN: New Buffalo, Berrien Co. (Daniels; Walker); High Island 
Harbor, Charlevoix Co. (Walker). 
Wisconsin: Lake Geneva, Walworth Co. (Illinois State Laboratory). 
GEOLOGICAL DistrRiBpuTION: Unknown. 
Ecotocy: Woodruffi probably inhabits the deeper waters of Lake 
Michigan as only dead shells have been found along the shore. 
Remarks: Woodruffi may be known by its very short, broad 
Spire, rapidly increasing and tumid whorls, its large, ovate or roundly 
ovate aperture and its broad, flat inner lip without a plait. It resembles 
emarginata in the form of its emarginate inner lip and catascopium 
in the general depressed form of the shell. The small size, large 
aperture and peculiar inner lip will distinguish woodruffi from both of 
these species. It somewhat resembles apicina but differs in the de- 
pressed spire and broad, flat inner lip, without a plait. The same 
feature will distinguish it from decollata. The shells vary somewhat 
in rotundity, some specimens being a trifle flattened on the body whorl 
and having the spire somewhat elevated. The shells vary some- 
what in the degree of umbilication which may be marked or absent. 
The aperture may also be roundly ovate, oblong-ovate or elliptical. 
With all this variation, however, the species seems quite distinct and 
is very uniform in its specific features. Young shells are quite thin, 
but adult specimens are very thick and solid and show a tendency to 
hecome imperforate as well as to acquire a tubercle or swelling on the 
middle of the columella. 
Since its discovery by Mr. F. M. Woodruff, in 1901, the species 
has been collected in large numbers all along the southern shores of 
Lake Michigan from Evanston, Illinois, to Michigan City, Indiana. 
This abundance of material is ample evidence that the species is liv- 
ing in goodly numbers somewhere in the deep water of the southern 
