CLASS PELECYPODA 
209 
Saxicava pholadis Linnaeus, 1771. 
Plate 51, fig. 5. 
Anim. s. Vertebres et Mantissa, 2:548. Sars, Moll. Reg. Arct. Norv.; pi. 20, figs. 
7, a-b. 
Shell elongated, rather mytilus-shaped, concentrically, strongly wrin¬ 
kled ; anterior side very short, rather narrow; posterior side more ex¬ 
panded, elongated, obliquely angular; dorsal margin straight; terminal 
margin broadly truncated; ventral margin convex. (Conch. Iconica.) 
Type in British Museum. Type locality, Greenland. 
Range. Arctic Ocean to Panama. Also Atlantic. 
Family PHOLADIDiE. 
Genus BARNEA (Leach) Risso, 1826. 
Shell oval-oblong, anteriorly gaping, a single lanceolate dorsal acces¬ 
sory valve; umbonal process reflexed, closely applied. (Tryon. S. S. 
Conch.) 
Type. Pholas Candida Linnaeus. 
Distribution. Australia, Burma, Red Sea, Europe, Patagonia, 
Philippines, United States, Norway, India, Western Africa, Crimea. 
Range in time. Eocene. United States and Europe. 
Barnea pacifica Stearns, 1871. 
Plate 21, figs. 2, 3, 4. 
Prcl. Descr.y Aug. 1871, p. 1. Proc. Cal. Acad. Sci. f 5:81; pi. 1, figs. 6, 6, a-c, 1873. 
Shell oblong, beaks two-fifths the 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 the valves squarely 
rounded; shell dull, chalky white, sculptured in concentric lines, which 
anteriorly are laminated and posteriorly 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, which varies much in promi¬ 
nence in different specimens; accessory plate sub-lanceolate and bent 
down on the beaks; anteriorly prolonged over but not covering the ante- 
umbonal gape; interior of valves white, enamelled; internal rib short, 
curved and flattened. Length, 2%o,* height, 1% 0 inches. (R. E. C. 
Stearns.) 
Type in U. S. N. M. Type locality, San Francisco Bay, California. 
Range. San Francisco Bay to Lower California. 
