MUSEUM OF COMPARATIVE ZOOLOGY. 181 
of the mantle; orifices of the combined generative organs behind and below 
the right eye-peduncle. (See 3d Suppl., Plate VIII. Fig. A.) 
Jaw arcuate, with numerous ribs. (Plate IX. Fig. B of same.) 
Lingual membrane with tricuspid centrals, bicuspid laterals, and quadrate 
denticulated marginals. (Plate IX. Fig. C of same.) 
Northwestern parts of North America, in the Oregon Region, 
Allied to Prophysaon, but distinguished by its more anterior respiratory 
orifice, its rudimentary shell-plate, and decided caudal pore. 
Phenacarion foliolatus, Govt. 
Color a reddish fawn, coarsely and obliquely reticulated with slate-colored 
lines, forming areolw, which are indented at the sides, when viewed by a mag- 
nifier, so as to resemble leaflets; the mantle is concentrically mottled with 
slate-color, and the projecting border of the foot is also obliquely lineated. 
The body is rather depressed, nearly uniform throughout, and somewhat trun- 
cated at the tip, exhibiting a conspicuous pit, which was probably occupied by 
a mucus gland. The mantle is very long, smooth, and has the respiratory ori- 
fice very small, situated a little in front of the middle. The eye-peduncles are 
small and short. Length 85 mm. 
Arion foliolatus, Goutp, Moll. U. S. Exp., page 2, Fig. 2, a, b (1852); BINNEY, 
Terr. Moll., II. 30, Plate LX VI. Fig. 2 (1851); W. G. Binney, Terr. 
Moll., IV. 6; copied also by Tryon and W. G. Binney, L. & Fr. W. 
Sh, 0.877, 
Phenacarion foliolatus, Coceres, The Nautilus, 1890, III. 126; W. G. BINNEY, 
8d Suppl. to Terr. Moll. V., p. 206, Plate VIII. Fig. A; Fig. B (shell- 
plate); Plate IX. Fig. B (jaw); Fig. C (dentition); Fig. D (genitalia). 
Discovery Harbor, Puget Sound (Pickering) ; Olympia and Seattle, Wash- 
ington (Hemphill). 
Dr. Gould adds to the above description these words (Vol. IT. p. 31): “ That 
this animal belongs to the genus Arion there can be little doubt, from the 
peculiar structure of the tail, as represented in Mr. Drayton’s figure, and from 
the anterior position of the respiratory orifice. It is a well marked species, 
characterized especially by the leaf-like areole by which the surface is 
marked.” 
It is. with the greatest pleasure that I announce the rediscovery by Mr. 
Henry Hemphill of this species, which has hitherto escaped all search by 
recent collectors. p It has till now been known to us only by the description 
and figure of the specimen collected by the Wilkes Exploring Expedition, 
almost fifty years ago, and given in Vols. II. and III. of Terrestrial Mollusks. 
A. single individual was found in December, 1889, at Olympia, Washington, 
and sent to me living by Mr. Hemphill. It can thus be described. (See 
Fig. A of Plate VIII. of 3d Suppl.) 
Animal in motion fully extended over 100 millimeters. Color a reddish 
