274 University of California Publications in Zoology [Vou. 14 
beaks small and very low, at about the anterior third of the length; lunule 
elongated, extremely narrow, nearly as long as the anterior dorsal slope; 
escutcheon linear or none; interior white, the pallial sinus moderate, pointed; 
internal margin delicately striated; hinge well developed, like that of P. lordi, 
with three entire cardinals and no anterior lateral tooth.’’ 
Length, 2 to 5 mm. 
Occurrence.—At stations D 5705 (1), D5739 (11), D 5748 (7), 
D 5755 (1), D5773 (1), D5785* (11, 4), D 5787 (23), D5799 (1), 
D 5822 B (16), D 5825 A (134), D 5826 B (32), D 5828 A (249, 6), 
D 5828 B (262), D 5830 A (4, 20), and questionably at D 5756, D 5778, 
D 5779, Red Rock. 
This species has not hitherto been reported as far south as San 
Francisco. It has been dredged by the ‘‘Albatross’’ only from the 
middle portion of the bay and the waters outside the Golden Gate. 
Living specimens were obtained at ten stations in depths ranging from 
31% to 40 fathoms, on bottoms which are predominately sandy. 
Bering Sea to San Diego, California (Orcutt). 
Range. 
PETRICOLIDAE 
Petricola Lamarck 
Petricola carditoides (Conrad) 
Plate 20, figures 6a and 6b 
Saxicava carditoides Conrad (1837), p. 255, pl. 20, fig. 8. 
Petricola carditoides, Arnold, R. (1903), p. 154. 
Description.—This species was described by Arnold (1903) as follows: 
“Shell of medium size and variable outline, generally oblong-oval, convex, 
thick; surface ornamented with fine, concentric, incremental lines, which some- 
times form irregular ridges, and by fine, wavy, radiating lines; hinge-area 
prominent; three cardinal teeth in each valve, the anterior one smallest; margin 
smooth.’’ 
Length, 14 to 45 mm. 
Occurrence.—At stations D 5808 (2), D 5809 (2), D 5846 (2, 11), 
“and questionably at D 5845. 
This species has been listed from this region by Carpenter and 
subsequent writers. Dredged by the Survey from the western portion 
of Golden Gate in 43 to 53 fathoms. Living specimens found as 
nestlers in pholadid borings at a depth of 45 fathoms. Also found 
by Mr. A. L. Barrows in similar situations between the tides on the 
shore of Goat Island. 
Range—Vancouver Island to Lower California (Dall). 
