256 University of California Publications in Zoology — [Vou. 14 
This common bivalve has been reported by Carpenter and by Wood 
and Raymond from this region. Obtained by the Survey at six 
stations, which are restricted to the Golden Gate and Raccoon Straits. 
The single living specimen was dredged from a rocky bottom near the 
north shore of the Golden Gate in 10 fathoms of water. Shells were 
dredged in 1234 to 53 fathoms. This being a sessile form it occurs 
only where suitable support exists, such as stones or large shells. 
Range.—Unalaska to Lower California. 
MytTimacrEa 
MYTILIDAE 
Mytilus Linnaeus 
Mytilus californianus Conrad 
Plate 18, figure 2 
Mytilus calfornianus Conrad (1837), p. 242, pl. 18, fig. 15; Carpenter 
(1863), p. 648; Wood and Raymond (1891), p. 55. 
Description.—This species was described by Conrad (1837) as follows: 
“Shell ovate elongated, inflated; anterior margin straight; posterior side 
emarginate; ribs not very numerous, slightly prominent, broad, rounded; lines 
of growth very prominent.’’ 
Length, 2 to 90 mm. 
Occurrence.—At stations D 5776 (2), D5808 (1), D5809 (1), 
D 5842 (1), Presidio shore (149), Bonita Point (72, 1). 
This common edible mussel has been reported by various authors 
from this region. It appears to be restricted to the intertidal areas 
outside the Golden Gate, extending inward as far as Fort Point and 
Lime Point. Living specimens were obtained by the Survey only at 
the shore stations at Bonita Point and Fort Point. Shells were dredged 
at three stations in water ranging in depth from 314 to 53 fathoms. 
Range—Unalaska, Aleutian Islands, to Socorro Island (Dall). 
Mytilus edulis Linnaeus 
Plate 15, figure 4; plate 43 
Mytilus edulis Linnaeus (1758), p. 705; Carpenter (1863), p. 643; Dall 
(1898c), p. 788; Wood and Raymond (1891), p. 55; Arnold, R. (1903), 
p- 118. 
Mytilus edulis var. glomeratus Gould, Carpenter (1863), p. 643. 
Mytilus trossulus Gould (1850), p. 344. 
Description.—Arnold (1908) describes this species as follows: 
“«Shell of medium size, wedge-shaped, rounded behind, thin; surface smooth, 
except for concentric, incremental lines; umbones terminal; dorsal margin 
slightly depressed in middle; hinge-teeth minute.’’ 
Length, 2 to 60 mm. 
