158 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Acmaea paleacea Gould, 1851 
Mexican and California Shells, 3: PL 14, fig. 5. 
T. parva, tenuis, elongata, lateraliter valde compressa et triangularis, 
ad dorsum utroque costis obtusis ornata; apice acuto prope trientem an- 
teriorem longitudinis sito; color straminea, vel cinnamomea. 
Shell minute, delicate, thin, elongated, laterally compressed, so that the 
two sides are parallel; dorsal aspect a long, narrow oval; lateral aspect low 
triangular; apex at about the anterior third, acute, antrorse; surface with 
delicate lines of growth, and a few obtuse radiating ridges along the 
dorsal slope at each end; color straw yellow, or cinnamon brown. 
Length, %; height, Y\o; breadth, in. 
On kelp or stems of Zoophytes, Santa Barbara. (Col. Jewett.) 
This curious little shell can be compared with no other species, unless 
it be A. alveus, which is still comparatively much broader. It has much the 
size and shape of a glume of wheat. 
Type in ? Type locality, Santa Barbara, California. 
Range. Trinidad, California, to Lower California. 
Acmaea triangularis Carpenter, 1866 
Proceedings of the California Academy of Sciences, 3:213. 
N. t. N. pallcacca simili, sed multo minus elongata; apice elate margini- 
bus rectangulatim devergentibus; albida, maculis fuscis perpaucis ornata ; 
striulis subobsoletis. Long., 0.28; lat., 0.12. (Carpenter.) 
The solitary shell sent by Dr. Cooper is shaped like a right-angled 
triangle, with five brown spots near the base. (Carpenter.) 
Type in State Collection, No. 416c. Type locality, Monterey, Cali¬ 
fornia. 
Range. Sitka, Alaska, to Gulf of California. 
Described as Nacella. 
SECTION RHODOPETALA Dali, 1920 
Acmaea rosea Dali, 1872 
Proceedings of the California Academy of Sciences, 4:270; PI. 1, fig. 2. 
Shell small, egg-ovate, of a deep rose color, externally smooth, except 
for very faint radiating ridges divaricating from the apex, and for lines of 
growth. Margin entire; apex minute, produced before the anterior margin. 
Interior smooth, white, except the margins, which are polished and of the 
same color as the exterior. Nacre, especially when weathered, silvery. 
Long., .35; lat., .27; alt., .12 in., of the largest specimen. (Dali.) 
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