394. THE CHICAGO ACADEMY OF SCIENCES. 
It was at first identified as niagarensis, but differs from that race in 
having a more elongated shell, a longer spire and hence longer spire 
whorls, and a more elongated and narrower aperture. The race 1s 
so characteristic that it cannot be mistaken for any other species or 
race. There is some variation in the shape and degree of impression 
of the inner lip and also of the aperture, but on the whole the race is 
unusually constant in general form. Several specimens have been seen 
in which the upper part of the whorls is distinctly shouldered. 
The race is common on the St. Clair flats near Detroit. Walker’s 
Michigan reference (op. cit. p 291), in which he says, “Associated 
with this form at Station IV, 6, (Small Island in Tobin Harbor, Isle 
Royale) was a very thin, elongated form with the characteristic sculp- 
ture of catascopium, which is closely related to, but much more fragile 
than, the elongated form which is characteristic of the lower Great 
Lakes,” appears to be referable to this race. 
The race-is named in honor of Prof. Chas. C. Adams, of the 
University of Illinois, who has contributed many valuable notes to the 
ecology of Michigan Mollusca. 
Galba davisi (Walker). Plate XLI, figure 5. 
Lymnea davisi WALKER, Nautilus, XXII, p. 17, pl. i, figs. 9-10, June 1908. 
“SHELL: Of medium size, globose-conic; perforate; light horn- 
color; whorls 5; the spire about one-third of the entire length of the 
shell, rapidly acuminating and with a minute, sharp apex; the whorls 
of the spire are flattened and but slightly convex, with a distinct, but 
not deeply impressed suture; body whorl large, inflated, ovate, flat- 
tened above and rounded below; lines of growth distinct, fine and regu- 
lar, minutely decussated with revolving spiral lines; aperture large, 
pear-shaped, acutely angled above and broadly rounded below, about 
three-fifths of the entire length, lip sharp, slightly thickened within, 
straight above, somewhat expanded below, broadly reflected over and 
nearly covering the small umbilical perforation; columella with a very 
slight fold; axis rather thick, round, scarcely if at all folded.” 
Length. Breadth. Aperture length. Breadth. 
15.20 7.50 9.00 4.00 mill. Type. 
15.00 7.50 9.50 4.50 os 
Type: Collection Bryant Walker, Detroit, Michigan, two speci- 
mens, No. 20092. 
Type Locaity: Fish Point, Tuscola Co., Michigan. 
ANIMAL, JAW, RApDULA and GENITALIA: Unknown. 
Rance: Tuscola Co., Michigan. A species of the humid division 
of the Transition life zone and of the Canadian region. 
