1918] Packard: Molluscan Fauna from San Francisco Bay 249 
surface, under a glass, the appearance of an overlapping. Epidermis shining, 
olivaceous; internally a bluish white; muscular sears large, the anterior tri- 
angular; posterior a third the largest, broadly suboval.’’ 
Gabb confused the terms posterior and anterior as applied to this shell. 
These words should be interchanged in the above description. 
Length, 55 mm. 
Occurrence.—At station D 5788* (7). 
This species is represented in the ‘‘Albatross’’ collections, by a 
single specimen, that was dredged alive outside the Golden Gate, in 
68 fathoms and on a bottom composed of a dark green sand. 
This specimen differs somewhat from the type of the species which 
is in the collections of the Department of Palaeontology of the Uni- 
versity of California, in that it is less produced anteriorly. 
Range.—San Francisco to San Diego, California. 
Yoldia ensifera Dall 
Plate 14, figure 6 
Yoldia ensifera Dall (1897a), p. 9, pl. 2, fig. 4. 
Description—This species was originally described by Dall (1897) as follows: 
“‘Shell large, thin, compressed, with a brilliant olivaceous periostracum, 
usually showing darker and lighter zones; valves nearly equilateral, moderately 
convex, rostrate, subarcuate; sculpture of fine lines of growth more or less 
evident, and on the anterior two-thirds of the shell numerous irregularly fluc- 
tuating, distant, incised grooves (like those of Y. scisswrata) which are absent 
on the posterior third; base arcuate, anterior dorsal profile rounded evenly from 
the beaks; a slight inward wave of the margin is visible anteriorly near the 
pedal gape; lunule absent; the escutcheon impressed, and the posterior dorsal 
margins of the valves, projecting vertically, blade-like, and slightly pouting; 
rostrum pointed, slightly recurved, beaks low, inconspicuous; valves internally 
whitish; pallial sinus deep, rounded; chondrophore wide, hardly projecting; 
teeth narrow A-shaped, slender, about 30 in front of and 24 behind the chon- 
drophore.’’ 
Length, 10 to 30 mm. 
Occurrence.—At stations D 5785 (1), D 5789 (7, 4). 
This species has not before been reported from this immediate 
vicinity. The two stations at which it was dredged are outside the 
Golden Gate. Living specimens were dredged at depths ranging from 
39 to 46 fathoms on a bottom composed of fine, dark green sand. 
Range.—Southeastern Alaska to San Luis Obispo, California 
(Dall). 
