1918 ] Packard: Molluscan Fauna from San Francisco Bay 287 
Panope Ménard 
Panope generosa Gould 
Panopea generosa Gould (1849d), p. 215, 
Glycimeris generosa, Carpenter (1863), p. 637; Dall (1898c), p. 831; Arnold, 
(1903), p. 182. 
Description—In describing this species and its several varieties Dall (1898) 
gives the following description of the typical form: 
“‘Shell large, rather thin, nearly equilateral, the beaks slightly anterior, 
the dorsal and ventral margins in the full grown shell parallel and nearly 
straight, the pedal margin evenly rounded, the nymph narrow, and the attached 
edge of the ligament very short; the pallial sinus wide and shallow.’’ 
Carpenter mentions this species among those occurring in this 
region. It is not represented in the Survey collections. 
Range.—Puget Sound to San Diego, California (Dall). 
ADESMACEA 
PHOLADIDAE 
Pholas Linnaeus 
Pholas pacificus Stearns 
Pholas pacificus Stearns (1873), p. 81, pl. 1, figs. 5, 6, 6a, 6b, 6e. 
Description—This species was originally described by Stearns (1875) as 
follows: 
“*Shell oblong, beaks two-fifths of length of shell from anterior end; anterior 
end of valves triangular, pointed; anterior dorsal edge of valves reflected and 
folded down on the umbos; lower anterior margin curved, forming a large 
elliptic-oval gape; posterior end of valves squarely rounded; shell dull chalky 
white, sculptured in concentric lines, which anteriorly are laminated and poste- 
riorly become extinct; valves radiately ribbed, which also become obsolete at 
the posterior end; at the intersection of the radiating and concentric lines the 
sculpture is pectinated; an area below the umbos nearly or quite destitute of 
sculpture, which varies much in prominence in different specimens; accessory 
plate sublanceolate and bent down on the beaks, anteriorly prolonged, but not 
wholly covering the ante-umbonal gape; figs. 6a, 6b (Stearns), show the varia- 
tion in the shape of the dorsal plate in different specimens; interior of valves 
white, enameled; internal rib short, curved and flattened.’’ 
Length, 20 to 60 mm. 
Occurrence.—At stations D 5810 (1), D5818 (1), D 5818 B (1), 
D 5821 (f.), D 5824 (1), D 5839 (4), D 5845 (6). 
The type specimen of this species was obtained from San Francisco 
Bay. This mud-borer has been obtained by the Survey at widely sepa- 
rated localities throughout the entire bay, in depths ranging from 1 
to 10 fathoms from bottoms that are predominantly muddy. 
Range.—San Francisco, to San Pedro, California. 
