266 University of California Publications in Zoology [Vou. 14 
Lasaea Leach 
Lasaea rubra (Montagu) 
Cardium rubrum Montagu (1803), p. 83, pl. 27, fig. 4. 
Kellia rubra, Gould (1841), p. 60, fig. 23. 
Lasaea rubra, Dall (1899c), p. $81. 
Description.—This species was described by Gould (1841) as follows: 
“*Shell minute, rather thick, sub-oval, very inequilateral, rather compressed; 
beaks rather prominent, and in contact, having before them a deeply excavated, 
elongated, smooth areola; ends broadly rounded, especially the posterior tip; 
basal margin scarcely curved and nearly parallel with the superior margin; 
surface marked with the lines of growth, eroded at the beaks, and covered 
with a purplish or dirty-brown rather thick epidermis. Within white and 
glossy; two muscular impressions and the palleal line directly connecting them, 
without any sinus, quite perceptible. Hinge consists, in the right valve, of a 
narrow, erect, central tooth, and an imperfect one each side, slightly detached 
from the edge of the valve; in the left valve, of a well-defined tooth on each 
side, barely separated from the edge of the valve, leaving a triangular vacancy 
between them to receive the central tooth of the opposite valve. 
Length, 1 to 2 mm. 
Occurrence.—At stations D 5766 (2), D 5771 (1), Presidio* (17). 
As far as is known this species has not been recorded from the 
vicinity of San Francisco. It is found in the Survey collection only 
from the middle and lower divisions of the bay. Living specimens 
were dredged from mud bottoms at depths of 3 and 314 fathoms. 
They were also taken at the shore station near the Presidio. 
Range—Vancouver, B. C., to Peru (Dall). 
CARDIACEA 
CARDIIDAE 
Cardium Linnaeus 
Cardium corbis (Martyn) 
Plate 20, figures la and 1b, pl. 44 
Pectunculus corbis Martyn (1784), pl. 28, fig. 2. 
Cardium corbis Carpenter (1863), p. 642; Wood and Raymond (1891), 
p. 55; Arnold, R. (1903), p. 140; Keep (1911), p. 72, fig. 47. 
Description.—This species was described by Arnold (1903) as follows: 
“‘Shell large, subtrigonal, ventricose, thick; umbones prominent, anterior 
to center; surface ornamented with about thirty-seven prominent regular, 
squarish, close-set, radiating ridges, which are made more or less rugose by 
incremental ridges on their surface; near the posterior margin these ridges 
become more rounded and less prominent; between the ridges are equal, deep, 
canal-like grooves; margin crenulated; ligament short, external, prominent; each 
valve with one prominent cardinal tooth, and two laterals, one anterior and 
the other posterior; muscle impressions prominent, subequal.’’ 
Length, 2 to 75 mm. 
