192 THE CHICAGO ACADEMY OF SCIENCES. 
ginal teeth aculeate. The teeth are similar in type to those of 
the Zonitide. 
Genitalia: Genital bladder ‘small, oval, on a long, deli- 
cate duct, from about the middle of the length of which there 
is a connecting duct to the middle of the penis sac and a second 
duct to the apex of the dart sac.” Penis long, large near the 
vagina, “tapering above, and furnished below its apex with an 
accessory, short, delicate, cylindrical gland, terminating in a 
small pyriform bulb. The dart is long, delicate, strictly arrow- 
shaped with pointed, enlarged head and much thickened at 
the posterior termination. The penis sac is stout, short, re- 
ceiving at its apex the vas deferens, on the commencement of 
which the retractor muscle is inserted.” * 
Distribution: Ontario, Canada, to Michigan, south to In- 
dian Territory, Louisiana, Virginia and Tennessee. (Pilsbry.) 
Geological distribution: Pleistocene of the Mississippi Val- 
ley; Loess. 
Halitat: Found rather sparingly in moist situations near 
bodies of water of greater or lesser size. Prefers the under 
side of old logs and the depths of dead brush heaps. 
Remarks: Easily recognized by its globose form, some- 
what elevated spire and deeply impressed base. It is nota 
common species, and, so far as known, is confined to the south- 
ern region, about the chain of lakes. 
74. Gastrodonta demissa Binney, pl. xxviii, fig. 6. 
Flelix demissa BINNEY, Bost. Journ. Nat. Hist., Vol. IV, p. 361, pl. 
xvi, fig. 16, 1843. 
Gastrodonta demissa britist? PILSBRY, The Nautilus, Vol. XI, p. 132, 
1898, (Variety.) 
Shell: Umbilicated, depressed, convex; epidermis as in 
ligera; whorls six, covered with coarse, closely crowded, trans- 
verse striz, disappearing on the base; umbilicus small, round, 
deep; umbilical region impressed; suture impressed; aperture 
transverse, oblique, the base of the last whorl with a deposit as 
in Zigera; peristome thin, acute; spire very much depressed, so 
that all the whorls cannot be seen when viewed laterally; base 
of shell flat, smooth; last whorl but little expanded toward 
the aperture. 
Greater diameter, 8.50; lesser, 7.25; height, 4.00; umbilicus diameter, 
0.50 mill, (8459.) 
Animal: Not differing in general form from d¢gera, color 
~ *W. G. Binney, Man. Am. Land Shells, p. 214. 
Ay’ i Ace eS peas 
