242 THE CHICAGO ACADEMY OF SCIENCES. 
“SHELL: Ovate, conic, turreted, umbilicate, light yellowish horn- 
colored, shining; lines of growth fine, irregular, subobsolete on the 
body whorl, stronger on the apical whorls, reticulated by indistinct 
revolving, impressed spiral lines. Spire elongated, apex subacute; 
whorls 5, very convex, those of the spire somewhat shouldered, suture 
deeply impressed; body whorl large, inflated, very convex. Aperture 
broad, oval, subcircular, rounded above and below. Columella broadly 
reflected over the round, deep umbilicus, convex, smooth with no fold, 
parietal wall with a thin transparent callus. Lip sharp, but thickened 
within by a heavy white callus.” 
Length. Breadth. Aperture length. Breadth. 
7.50 3.25 one ; Type (Walker) 
rita) 4.25 3.80 2.50 Cotype 
Types: Collection Bryant Walker, three specimens, No. 13599. 
Type Locarity: Indian Creek, Kent County, Michigan. 
ANIMAL, JAW, RApULA and GENITALIA: Unknown. 
RANGE: Michigan to New York. A species of the Canadian 
region and of the Transition life zone. 
RECORDS: 
MicHicAN: Indian Creek, Kent Co., Alma, Gratiot Co. (Walker). 
New York: Ellicott Creek, Williamsville, Erie Co. (Miss. Walker). 
GEOLOGICAL RANGE: Unknown. 
Ecotocy: Not recorded. 
ReMARKS: Cyclostoma may be known by its peculiar cyclostomoid 
aperture and very obese body whorl. It combines characteristics of 
both uwmbilicata and parva and has been derived, doubtless, from the 
same stock. It approaches closer to parva in its rounded whorls and 
acute spire. It strongly resembles certain forms from Des Moines, 
Iowa (pl. XXIX, figs. 5-7), differing in the form of the aperture, 
the body whorl and the inner lip, as well as in sculpture. 
“This very distinct little species was first collected by Dr. R. J. 
iXirkland, of Grand Rapids, Michigan, and was listed as L. cubensis 
Pfr. (umbilicata C. B. Ads.) in my Review of the Moll. Fauna of 
Michigan (1894). Through the courtesy of Mr. E. A. Burt, curator 
of the Museum of Middlebury College, I have been able to examine 
the specimens of L. umbilicata deposited in that museum by Adams. 
The two species are so obviously distinct that verbal comparison is 
hardly necessary. L. cyclostoma differs in its more elevated, turreted 
spire, more broadly reflected columella and thickened white lip. It 
resembles umbilicata, however, in the sculpture, and is no doubt de- 
rived from the same stock.” Cyclostoma will probably be found in 
many collections, labeled humilis or parva. 
