30 NEW-YORK FAUNA— MOLLUSCA. 
HELIX ARBOREA. 
PLATE Il. FIG. 10. a. B. c.—(STATE COLLECTION.) 
Helix arborea. Say, Nich. Ency. Vol. 4, pl. 4, fig. 4. 
SET Saeed Binney, Bost. Jour. Nat. Hist. Vol. 3, pl. 26, fig. 1. 
ad. GouLp, Invertebrata of Mass, p. 182, fig. 110. 
i: iad. Apams, Am. Journal Science, Vol. 40, p. 273. 
He. id. WHEATLEY, Catalogue of Shells of U. S. No. 494, p. 19. 
Description. Shell small, thin, fragile, orbicular, pellucid, depressed, very little elevated ; 
concave beneath. Whorls four to five, slightly rounded above, with a distinct suture, and 
minutely wrinkled irregularly in the direction of the lines of growth; beneath smooth, with 
a wide and deep umbilicus. Aperture sublunated. Lip simple, thin and brittle, its junction 
with the body-whorl acute. ; 
Color. Corneous, occasionally deep brown and even blackish. Animal with a dusky head 
and neck, lighter behind. 
Diameter, 0°2. Height, 0°13. 
The species has a wide geographical range. It has been observed at Troy in this State by 
Dr. Newcomb, and at Staten island in Rockland county. According to Dr. Gould, it may 
be confounded with H. cellaria, indentata, gularis and electrina. It is smaller than the first ; 
has not the distant impressed radiating lines of the second, nor the peculiar tooth within the 
aperture of the third, and is distinguished from electrina by its greater number of whorls and 
less polished appearance. 
HELIx ELECTRINA. 
H. electrina. Gou.p, Invertebrata of Mass. p. 183, fig. 111. 
A, id. Apams, Am. Journ. Science, Vol. 40, p. 273. 
Description. Shell small, orbicular, depressed, conical, pellucid, fragile, and the lowest 
whorl suddenly enlarging as in H. indentata. Whorls four, conspicuously wrinkled by the 
lines of growth. Lip moderately thick and shining ; its outline nearly a direct section of the 
whorl. Umbilicus moderate, smaller than in the preceding. Aperture rounded. Color, 
amber. 
Diameter, 0:2. Height, 0:13. 
Dr. Gould, to whom we are indebted for this species, speaks of it as resembling indentata 
above and arborea beneath. It is certainly very closely allied to both. It has been noticed 
in Massachusetts and Missouri. I have not seen it, but Dr. Newcomb has found it near Lake 
George in this State. 
