1918 | Packard: Molluscan Fauna from San Francisco Bay 267 
Occurrence.—At stations D5700* (1, 17), D5701 (1), D5702 
(4, 19), D 5708 (7), D 5704 (3), D5705 (1 ae D 5706 (4), D 5708 
(6, 8), D 5709 (3, 3), D5710 (2), D 5711 (2), D 5712 (3), D 57138 (6), 
D 5714 (14,1), D 5715 (1), D 5728 (2, 5), DE a Nea D 5725 (1, 2), 
Dai26r (4), Diat2sn(2l)s Disi29 (2) Diets! (3), D573 (7.5), 
D 5732 (£:), D586 (£), D57387 (£.), D5739 (8, 1), D5740 (7), 
D 5741 (f.), D5742 (18), D5748 (6, 46), D5744 (6, 5), ae 
(25 15), DibT46 (2, 2), Dis747 (1); D'5748' (3), D 5750 .), D'S 
Ci) Dinto2o(3), Dibfo£ (2,95), D 555 (32), IDst56: (2), D 57 
(29, 1), D 5764 (1), D 5766 (3, 10), D 5767 (3, 8), D 5768 (7), 5 5772 
(Ce Dibifeaats)Diniis. (2. lo). 5079) (C2: 8), D' Srs0n)D'5782 
(1), Dots! G:), D5795 (7, 11); D5796 (27,19), Dem9s, (1), 
D 5799 (1), D5800 (16), D5801 (2, 1), D5802 (1), D5803 (2), 
D 5808 (2), D 5809 (2), D 5821 A (7, 2), D 5821 B (7, 1), D 5822 B 
(3), D 5823 (7, 1), D5823 A (51), D5824 B (19), D5825 (1, 4), 
D 5825 A (9), D 5825 B (1), D 5826 (3), D5826 A (6), D 5826 B 
(5), D 5827 (12), D 5827 A (7), D 5828 (2), D 5828 B (16), D 5829 A 
(7), D 5831 (1, 2), D 5832 (2), D 5833 (29), D 5834 (4), D 5835 (2), 
D 5839 (1), D 5841 (11), D 58438 (1), D 5844 (1), D 5847 B (1). 
This common West Coast cockle has been reported by a number 
of writers from this region. It has a general distribution, being more 
frequently taken within the middle division of the bay. Living speci- 
mens were dredged at forty stations in depths ranging up to 19 fath- 
oms. About two-thirds of these hauls were made in less than 10 
fathoms. It appears to be predominately mud-dwelling species, 
although it occurs on all types of bottom. 
Range.—Bering Sea to San Diego, California (Dall). 
rk 
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7 
7 
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Cardium (Protocardia) centifilosum Carpenter 
Plate 20, figures 2a, 2b, 2c, and 2d 
Cardium var. centifilosum Carpenter (1863), p. 642. 
Protocardia centifilosa, Dall (1900a), p. 1113; Arnold, R. (1903), p. 142. 
Description.—The following is Arnold’s (1903) description of this species: 
‘«Shell small, suboval, ventricose, thin; umbones central, prominent, only 
very slightly bent; surface sculptured by numerous fine, close-set, rounded, 
radiating ridges, which are made slightly rugose by numerous fine, incremental 
lines on their surface; thin, sharp teeth in each valve; pallial sinus shallow, 
wide; margin beautifully and sharply serrate.’’ 
Length, 3 to 14 mm. 
