60 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
SECTION LITTORIVAGA Dali, 1918 
Littorina aleutica Dali, 1872 
Proceedings of the California Academy of Sciences, 4:271; PI. 1, fig. 3. 
Shell depressed, whorls four, the nucleus including one and a half. 
Last whorl much the largest; spire depressed or nearly flattened. Color 
variable, from dark brown or purple to waxen white, or banded with white 
on a darker ground. Nucleus polished, dark brown, translucent. Sculp¬ 
ture consisting of rather coarse lines of growth, and about six or eight 
nodulous revolving ridges more or less strongly elevated in different speci¬ 
mens, the three middle ones being the most prominent, and faint revolving 
lines being also traceable occasionally between the ridges. Aperture very 
oblique, smooth, white or purplish within, outer lip sharp, columella broad, 
straight, generally with a chink behind it. Anterior margin a little pro¬ 
duced. Long., .41; lat., .53 in. of an average specimen. (Dali.) 
Type in United States National Museum. Type locality, Gull Rocks, 
Akutan Pass, Aleutian Islands. 
Range. Pribilof Islands and the Aleutians from Kyska to Chika 
Islands. 
Littorina sitchana Philippi, 1845 
Proceedings, Zoological Society of London, 140. Tryon, Mamial of Conchology, 
9 : 240; PI. 41, fig. 90. 
Subglobose, moderately solid, strongly spirally ridged, usually with 
subequal intervening furrows; dark chocolate color, often with a broad 
white peripheral band, interior chocolate. Length, 15-18 mm. (Tryon.) 
Type in British Museum. Type locality, Vancouver Island, British 
Columbia ? 
Range. Southern Bering Sea, both coasts and southward; Puget 
Sound. 
Littorina atkana Dali, 1886 
Proceedings of the United States National Museum, 9:211. Ibid., 24:551; PI. 39, fig. 11. 
Typical form of shell large, solid, nearly smooth, the whorls flattened 
next the suture, a few obsolete striations on the base, the general form as 
figured, the outer lip thin, the pillar broad and white. Alt., 20.0; lat., 17.0 
mm. (Dali.) 
The most abundant form is of a dark chestnut brown throughout, ex¬ 
cept on the pillar. The variety figured has white bands at the suture, 
periphery, and umbilical region. These bands do not vary in position. 
(Dali.) 
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