1918 | Packard: Molluscan Fauna from San Francisco Bay 267 
Occurrence.—At stations D 5700* (1, 17), D5701 (1), D 5702 
(4, 19), D 5703 (7), D5704 (3), D5705 (15), D5706 (4), D5708 
(6; 8), D’5709) (3,3), D5710 (2), D5711 (2); Di 5712 (3), D 5713 (6 
DSA (4 1)e Dolby (2), Didi23(255) 5 Diai24 (4). Disr25 (2,2), 
DSi265(4)5 Diai28 (25 1); DisT29 (2) Dists0)(3)— Dibi3lt (ied), 
IDEVe2 (Gi), ID SEIS (Gis IDE (Gin), ID Eee (Ee AD), IDE (ZAR 
D 5741 (f.), D5742 (13), D5748 (6, 46), D 5744 
(6 5), D5745 
(2, 15), D 5746 ( c 2), D 5747 (1), D 5748 (3), D5750 (f.), D 5751 
(£.), te @), 5754 (2, 5), D5755 (32), D5756 (2), D5757 
(29, 1), D 5764 ( ee, ge in D 5767 (3, 8), D 5768 (1), D 5772 
@. ane (3) ge (1), D 5782 
(1, 1), D 5784 (£. 
D 5799 (1 ) D 580 
D 5808 (1), 09 (2 
(3), D 5823 ee 
B 
* 5798 
8. D5 Cs (2, 1 ; oe 5802 (1), D 5803 
5821 A (1, a 5821 B (1, 1), D 5822 B 
1D), en (51), ae B (19), D5825 (1, 4), 
D 5825 A (9), D 5825 B (1), D 5826 (3), D 5826 A (6), D 5826 B 
(5), D 5827 (12), D 5827 A (7 ), D 5828 (1), D 5828 B (16), D 5829 A 
(7), D'5831 (1,2), D 5882) (2), D 5833 (29), D5834 (4), D 5835 (2), 
D 5839 (1), D 5841 (11 , D 5843 (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). 
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. 
