FAMILY HELICID — HELIX. 29 
HeELix THyYROIDUS. 
PLATE II. FIG. 8. a. 3. ImmarurE.— (STATE COLLECTION.) 
Cochlea umbilicata, Lister, Conch. pl. 91, fig. 91. 
Helix thyroidus. Say, Nich. Encye. Vol, 4. Ip, Acad. Nat. Sc. Vol. 2, p. 161. 
H. id. Ip. American Conchology, pl. 13, fig. 1. 
H. id. Ferrussac, Histoire des Mollusques, pl. 49, A. fig. 4. 
HH. thyroidienne. Lamarck, An. sans vert. Ed. Brux. Vol. 3, p. 309. 
H. thyroidus. Govup, Invertebrata of Mass. p. 171. 
Description. Shell rounded, convex. Whorls convex, about five in number, with minute 
parallel oblique strie ; the suture distinctly impressed. Aperture moderately large, lunate. 
Lip broadly reflected, and partially covering the umbilicus. Pillar-lip in the adult with an 
oblique tooth. Umbilicus exhibiting one volution, and sometimes entirely closed. 
Color. Epidermis yellowish brown. Animal granulated, and of a soiled yellow. 
Diameter, 0°5 — 0°8. 
We have strongly marked varieties in this vicinity of a light chocolate-brown, with dis- 
persed dark spots, and interrupted revolving lines; the pillar-lip smooth; diameter 0:8; 
animal of a light amber-color. I have thought that it would be more instructive to give this 
variety in the plate above referred to, than the typical form, which may be found in most of 
our conchological works. 
This species is common in moist shady places, from New-York to Missouri. It is more 
rare in the Eastern States. 
HELIX ALTERNATA. 
PLATE Il. FIG. 9.—(STATE COLLECTION.) 
Helix alternata. Say, Nich. Ency. Vol. 4, pl. 1, fig. 2. Ip. Jour. Acad. Nat. Sc. Vol. 2, p. 161. 
Hi. scabra, Lamarck, An. sans verteb. Ed. Brux. Vol. 3, p. 292 
H. alternata. Govuxn, Invertebrata of Mass. p. 177. Apams, Am. Jour. Vol. 40, p. 273. 
Description. Somewhat depressed, slightly convex above. Whorls five or six, flattened, 
and roughened above with lines of growth; smooth beneath. In young specimens, there is a 
prominent ridge between the upper and under surfaces. Lip simple, thin and brittle, and 
regularly curved. Umbilicus wide and deep, exhibiting all the volutions. 
Color. Epidermis dusky. Shell light brown, alternating or varied with zigzag bars of 
deep reddish brown, becoming smaller as they converge towards the umbilicus. These bars 
are interrupted by a light colored revolving band. Lip within glossy and pearly. Animal: 
Head and tentacles light slate ; back brown; remainder of the upper surface brownish orange. 
Diameter of the shell, 0°8 — 1:0. 
Common every where in ditches and moist places, and under the bark of decaying trees. 
Its geographical limits southwardly and westwardly not known. It has been observed from 
Maine to Maryland. As Deshayes has properly observed, the name imposed by Lamarck 
must be expunged, that of Say having distinctly the priority. 
