150 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
with the characteristic dark brown stain of patina in the visceral area. 
The exterior is covered with fine, regularly radiating, close, equal, thread¬ 
like riblets, which pass from apex to margin without bifurcation, imbri¬ 
cation, or asperities of any kind. These riblets will serve to distinguish it 
from any of the other limpets of the coast; otherwise it approaches very 
close to some varieties of scabra, and can be traced right into varieties of 
patina . The variations of these limpets appear to be absolutely without 
limits; you may describe seven hundred forms as easily as seven. The 
only guide to specific identity is a certain habit of growth, easier seen than 
described, and very easy to overlook. (Dali.) 
Type in United States National Museum. Type locality, Monterey, 
California. 
Range. Known only from type locality. 
Acmaea apicina Dali, 1879 
Proceedings of the United States National Museum, 1:341. Tryon and Pilsbry, 
Manual of Conchology, 13:24; Pi. 7, figs. 66, 67. 
Testa parva, conica, tenui, rotundata, plus minusve elevata; albida seu 
isabellina, apice erecto, luteo; intus luteo, albido, seu fusco, laevi; extus 
striulis increments subobsoletis, munito. Lat., 5; long., 6; alt., 4 mm. 
(Dali.) Mi 
Shell small, conical, thin, rounded, more or less elevated; whitish or 
isabelline, the apex erect, buff; inside buff, whitish or brown, smooth; 
provided with subobsolete lines of growth outside. (Dali.) 
Type in United States National Museum. Type locality, Pribilof 
Island. 
Range. Pribilof, Aleutian, and Shumagin Islands, Alaska. 
Acmaea peramabilis Dali, 1872 
Proceedings of the California Academy of Sciences, 4:302. Tryon and Pilsbry, 
Manual of Conchology, 13: PI. 33, figs. 80-82. 
Shell thin, delicate, ovate; externally of a uniform dark rose color, 
with a few scattered irregular blotches of light or dark brown, nucleus 
pale. Within polished, bluish white, with a chestnut brown spectrum with 
sharply defined edges, outside of which for a short distance the white is 
unsullied, but further toward the margin in adult specimens, radiating 
brown blotches may be observed forming a more or less interrupted band 
around the shell, which is wanting in the young. The margin is of the 
same deep rose as the exterior. Shell moderately elevated, with the apex 
well marked subacute and situated in the central third. Nucleus smooth, 
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