1918] Packard: Molluscan Fauna from San Francisco Bay 25 
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ANOMIACEA 
ANOMIDAE 
Anomia Miiller 
Anomia peruviana d’Orbigny 
Plate 15, figures 2a and 2b 
Anomia peruviana d’Orbigny (1835-43), p. 673; Dall (1910b), p. 148, pl. 28, 
fig. 4. 
Anomia lampe Gray, Arnold, R. (1908), p. 117. 
Description.—Dall described this species as follows: 
“‘Shell very thin, pearly; white or copper brown on the upper valve, bluish 
green internally and on the central part of the lower valve; sessile on other 
shells or smooth objects adhering by a prominent byssus which passes through 
a large hole in the lower valve. The scars of the muscles in an area on the 
inside of the upper valve form a nearly even straight row radiating from the 
direction of the hinge.’’ 
Length, about 26 mm. 
Occurrence.—At station D 5811 (3). 
Three worn valves dredged within the lower part of the bay have 
been referred to this species. Its association with the eastern oyster 
suggests the possibility of it bemg Anomia simplex d’Orbigny, an 
eastern form closely resembling our West Coast species. However, 
Anomia peruviana has recently been reported by Clark (1914, p. 25) 
from Bolinas Bay, so it is not improbable that it is living within San 
Francisco Bay. The specimens were obtained from a muddy bottom 
at a depth of 3 fathoms. 
Range—Bolinas Bay, California (Clark), Paita, Peru (Dall). 
Monia Gray 
Monia macroschisma (Deshayes) 
Plate 15, figures la and 1b 
Placunanomia macroschisma, Carpenter (1863), p. 646; Wood and Ray- 
mond (1891), p. 55. 
Pododesmus macroschisma, Arnold, R. (1903), p. 116. 
Description—This species is described by Arnold (1903) as follows: 
‘‘Shell adherent, subequivalve, irregular, flattened; hinge with two thick, 
divergent, elongated lamella in the inferior, corresponding with two long pits 
in the upper valve; upper valve with only two muscular impressions; the pedal 
sear radiately striated; surface with incremental laminae and sometimes radial 
ridges.’’ 
Length, 15 to 80 mm. 
Occurrence.—At stations D 5700 (1), D5702 (2), D5775 (1), 
D 5795 (£.), D 5796 (1), D 5800 (2), D 5809 (f.). 
