248 University of California Publications in Zoology — [Vou. 14 
Leda taphria Dall 
Plate 14, figures 7a, 7b, and 8 
Leda taphria Dall (1897a), p. 7, pl. 2, figs. 6 and 8. 
Leda coelata Hinds, Carpenter (1863), p. 644; Arnold, R. (1903), p. 98, 
pl. 17, fig. 5. 
Description.—This species is described by Arnold (1903) as follows: _ 
“*Shell small, trigonal, oblong and rounded in front, produced and pointed 
behind; surface sculptured by numerous sharp, concentric, raised lines; umbones 
central, turned toward posterior end; escutcheon long, narrow and concentrically 
striated; hinge with prominent internal cartilage-pit, and about twenty sharp 
teeth on each side; pallial line with a small sinus; umbonal area with a linear 
impression joining the anterior adductor.’’ 
Length, 4 to 20 mm. 
Occurrence.—At stations D 5772 (1), D5785* (10, 7), D5786 
(G5 )5 ID) Bitte (2 1D) Warns) (())5 1D) sii) (aD), ID Sieeal (GE G), ID ETez 
(2). 
Carpenter lists this species from this region. Living specimens 
were dredged by the Survey at eight stations, all but one of which 
are situated outside of the Golden Gate. The exception is a single 
living specimen recorded from station D 5772, near Sausalito. The 
depth of the water at that station is but 114 fathoms, whereas those 
occurring in the open ocean lived in water ranging from 19 to 68 
fathoms. The bottom consists of fine dark, green sand, which differs 
markedly from the soft mud bottom found at D 5772. This species 
appears to be more abundant than Leda hamata, with which it is 
associated. 
Range.—Bodega Bay to San Diego, California. 
Yoldia Miiller 
Yoldia cooperi Gabb 
Plate 14, figure 9 
Yoldia cooperii Gabb (1865), p. 189; Gabb (1869), p. 31, pl. 9, fig. 54; 
Arnold, R. (1903), p. 99. 
Description—tThe following is the original description of this species as 
given by Gabb (1865): 
‘«Shell thin, somewhat compressed, very inequilateral, beaks placed about a 
third of the length from the anterior end, minute; anterior end narrow; sub- 
acuminate, posterior end broadly rounded; base most prominent just posterior 
to the middle of the shell; surface sculptured by numerous small concentric 
ribs, rarely dichotomous or anastomosing on the widest part of the shell; these 
ribs are flat and abruptly truncated on the side nearest the beak, giving the 
