160 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
The shell resembles that of the Patellidae, but the animal is more nearly 
allied to the Fissurellidae. (Dali.) 
Type. Cocculina rathbuni Dali. 
Distribution. In nearly all parts of the deep sea which have been 
explored. 
Cocculina agassizii Dali, 1908 
Bulletin, Museum of Comparative Zoology, 43: No. 6, 340. 
Shell small, white, covered with a strong light, olive-colored periostra- 
cum, beneath which it is chalky, ovate-quadrate, high, with the apex about 
the posterior third, and the anterior longer slope roundly arcuate; the 
periostracum is finely, closely, radiately threaded, the threads seem to bear 
very short projecting hairs, but neither the threads nor the hairs appear 
to correspond to any sculpture of the shell; on drying, the periostracum 
immediately detached itself from the upper part of the shell, showing 
beneath it only very fine, irregularly concentric lines; toward the margin 
it seemed to be more closely attached to the shell and by its contraction in 
drying, began at once to split the shell, obliging me to return it at once 
to the liquid from which it had been taken, or it would have gone to pieces 
entirely; interior of the shell smooth, white, with a broad, short, horseshoe¬ 
shaped muscular impression with a wide anterior hiatus at about the 
anterior third of the length; nucleus small, bulbous, produced hardly spiral, 
but decurved; the shell enlarges suddenly on entering the nepionic stage. 
Alt., 2.0; length, 3.5; width, 2.5 mm. (Dali.) 
Type in United States National Museum, No. 110660. Type locality, 
U.S.S. “Albatross” Station 4630, Gulf of Panama, in 556 fathoms. 
Range. Off Queen Charlotte Islands, British Columbia, in 150 fath¬ 
oms, to Gulf of Panama. 
Cocculina cazanica Dali, 1919 
Proceedings of the United States National Museum, 56:356. 
Shell small, brownish or whitish, darker toward the apex, which is at 
the posterior third of the shell; both slopes slightly convex, the nuclear 
point always eroded; sculpture near the apex minutely equally reticulate, 
the sculpture coarser and the radial threads more prominent than the con¬ 
centric ones toward the margin; interior polished, the muscular impression 
perceptible but not conspicuous. Length, 5.5 ; width, 4.5 ; height, 2.25 mm. 
(Dali.) 
Type in United States National Museum, No. 222069. Type locality, 
U.S. Fish Commission Station 4245, in Kasa-an Bay, Alaska. 
Range. Kasa-an Bay and Stephens Passage, Alaska, in 95-160 
fathoms. 
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