VITRINA PELLUCIDA. 11 
Idaho—(Pilsbry, Proce. Acad. Nat. Sci. Philad., 1889, p. 196). 
Nevada—Sierra Nevada (Call, l.e.). 
Nebraska—Rare, Cedar and Knox Counties (Aughey, Surv. 'Terr., 1877, p. 698). 
California—Carson Valley and Nevada to Owen’s Valley (Binney and Bland, 
Man., 1869, p. 28). Banks of Lake Tahoe, J. G. Cooper, and all over California 
as far south as Fresnoe Co. (Binney, Manual, 1885, p. 480). 
British Columbia—Nanaimo, Vancouver Island (Dall, op. cit.). 
Alaska—Muir Inlet; St. Paul, Kadiak Island; Popof and Unga Islands of the 
Shumagin group; Akutan, Unalga, Rooluk, and Unalaska of the Aleutian chain ; 
St. Paul and St. George Islands, Behring Sea, in tall grass of bluff, fifty feet above 
the sea (Dall, op. cit., p. 35). 
V. pellucida limpida Gould in Agassiz, Lake Superior, 1850, p. 243. 
Vitrina pellucida WeKay, Zool. N.Y. Moll., 1843, p. 25, pl. iii., f. 42. 
Vitrina americana Pfeiffer, Proc. Zool. Soc. London, 1882, p. 156. 
(ane Mr. Bryant Walker, of Detroit, 
Michigan, U.S. A., the East 
American form, V. émpida, 1s 
here dedicated, in cordial acknowledg- 
ment of his great influence and energy 
in the promotion of the study of 
American conchology, in which he bim- 
self is so accomplished a student, as 
well as in grateful appreciation of the 
invaluable and consistent help he has 
rendered in the preparation of the 
“Monograph.” 
ANIMAL whitish, greyish, or blackish ; 
head, tentacles and eyes black; tentacles 
very short ; SHELL more globose and smaller 
than alaskana. 
The MANDIBLE does not differ appreciably 
from that of V. pellucida, and although the 
figured specimen (fig. 19) shows certain small 
differences, these were not confirmed in the 
additional specimens examined. 
The LINGUAL MEMBRANE is stated by 
Binney to have the formula 30+1+30, with 
nine perfect laterals; another example 
showed 39+1+439 with ten perfect laterals, 
while Morse records a Maine specimen as 
possessing thirty rows of teeth with a formula 
of 25+1+25 and nine laterals. A Pennsylvanian specimen sent by Mr. G. Hi, 
Clapp did not agree with the descriptions or figures given by Morse or by Binney, 
but was in accord with that of the type form as figured on p. 6 of the present volume. 
WEE ZX 
Fic. 17. Fic. 18. Fic. 19. Fic. 20. 
Fic. 17.—Median, admedian, and marginal teeth of ”. Zimpida Gould, magnified (after W. G. Binney). 
Fic. 18.—Jaw of I’. dimpida Gould, highly magnified (after W. G. Binney). 
Fic. 19.—Jaw of V. dimpida Gould x 30, from Leetsdale, Pa., U.S.A., collected by Mr. G. H. Clapp 
and prepared by Mr. W. Moss. 
Fic. 20.—Shell of Vitrina limpida Gould (after W. G. Binney). 
This form is the eastern American variety, extending from New York on the 
east to Alberta on the west, and from Pennsylvania in the south to Hudson Bay 
Territory on the north. Dr, Dall is of opinion that the specimens reported from the 
Rocky Mountains by Ingersoll are really referable to alaskana. 
