J. W. Dawson—Paleozoic Land Snails. 413 
dohyalina of Morse, with the living species mznuscula and exigua. 
e thought it best, however, to place it in the subgenus Conulus 
of the genus Zonites, as defined by Messrs. Adams. Wit 
regard to the subgeneric name, Dr. Carpenter explained that 
the subgenus Conulus of Fitz, 1833, appears to be synonymous 
with Zrochiscus Held, 1837 (non Sby.); also with Petasia Beck, 
1837; and with Perforatella Schlitt. ; and according to Adams 
is a subgenus of Zonites Montf. (non Leach, Gray). Those 
who do not care to enter into these subgeneric distinctions, 
may designate the species as a Zonites, or even, speaking loosely, 
as a Helix. There seems nothing in its characters to separate 
it, more than specifically, from many of our smaller helicoid 
snails with thin shells and simple aperture. 
5. Dawsonella Meeki Bradley. (Figs. 12 and 13.) 
pBerors of Geological Survey of Illinois, vol. iy, p. 254. Am. Journ. of Sci., II, 
vol. iv, p. 88. Ibid, vol. vii, p. 157.] 
Description.*—Shell broad, depressed, helicoid. Spire ob- 
tuse, consisting of three to three and one-half turns. Length 
three and two-tenths millimeters, width four millimeters. Sur- 
face smooth, but with fine microscopic lines of growth, about 
fifteen in a millimeter. Aperture oblique, oval, greatly con- 
tracted by a broad lamellar expansion of the columella, extend- 
ing more than half way across, even in small individuals. 
Outer lip thickened, slightly reflexed. Suture little impressed, 
imperforate, but last turn slightly excavated in the umbilical 
region. The shell is usually black in color, and under the 
microscope shows no distinct structure, from which it may be 
inferred that it was corneous in texture. It is thicker than the 
shell of Zonites priscus. 
This species is found along with Pupa Vermilionensis, and was 
discovered by Bradley, who was, however, at first disposed to 
refer it to genus Anomphalus of Meek; but subsequently, and 
with good reason, regarded it as distinct and as a land shell. 
In size and general form it resembles Zonites priscus, though 
expanding less rapidly and with rounder whorls; but it is at 
once fk ae by its want of the somewhat coarse sculpt- 
ure of that species, and by the plate which partially covers its 
aperture. Its nearest modern allies in eastern America would 
s be such shells as Helix (Triodopsis) palliata, and H. 
(Stenotrema) monodon. 
or specimens of this shell I am indebted to the persons 
above named as having furnished specimens of Pupa Vermil- 
tonensis. 
6. Strophites grandeva, s.n. (Fig. 15.) 
Description.—Shell cylindrical, with obtuse apex. Whorls 
four or more. Surface covered with sharp’ vertical ridges, 
* Modified from Bradley. 
