234 BULLETIN OF THE 
in the smaller number of teeth, and in the size and position of the cartilage 
pit, which in Y. regularis is very large, and situated a considerable distance 
behind the beak. 
Leda quadrangularis Datu. 
This Bulletin, XII. p. 253, pl. 8, fig. 6, 1886; Bulletin U. S. Nat. Mus., No. 387, p. 42, 
pl. 8, fig. 6, 1889. 
A single right valve, Station 321, off Charleston, S. C., in 233 fathoms. 
This specimen is broken away on the posterior ventral margin, but in general 
outline agrees well with Mr. Dall’s figure. There is, however, a marked dif- 
ference in the number of teeth ; besides the principal ones, six before and eight 
behind the beak, as mentioned by Mr. Dall, there are four minute ones on 
either side of an exceedingly narrow (microscopic) smooth space (not a pit) 
directly beneath the beak. The hinge margin is also remarkably wide and 
strong in my specimen. 
From Cape Hatteras, N. C., to Cuba, in 683 to 1,568 fathoms, dead (Dall). 
Leda acuta Conran. 
Leda unca, Verrill, Trans. Conn. Acad., V. p. 572, pl. 58, fig. 41, 1882. 
Leda acuta Verrill, op. cit., VI. p. 259, pl. 80, fig. 15, 1884. 
Dall, this Bulletin, XII. p. 251, pl. 7, figs. 3a, 3b, 8, 1886; XVIII. 
p. 438, 1889; Bulletin U.S. Nat. Mus., No. 37, p. 44, pl. 7, figs. 3, 8; 
pl. 45, fig 15; pl. 64, fig. 140, 1889. 
One living, Station 345, south of Martha’s Vineyard, in 71 fathoms. 
Found by the U.S. F. C. from south of Martha’s Vineyard to off Cape Hat- 
teras, N. C., in 43 to 225 fathoms ; not living in less than 63 fathoms, or below 
155 fathoms. 
Also recorded by Mr. Dall as far south as the West Indies, in 54 to 80 
fathoms, dead. 
Leda pernula (Mitt.). 
VeERRILL, Trans Conn. Acad., V. p. 572, 1882; VI. p. 280, pl. 30, figs. 14, 14 a, 1884. 
One living, Station 331, off Cape Hatteras, N. C., in 898 fathoms. 
A rare species found by the U.S. F. C. from off Cape Race, Newfound- 
lana, to off Chesapeake Bay, in 25 to 479 fathoms. 
Malletia obtusa (M. Sars) Mércn. 
VERRILL, Trans. Conn. Acad., VI. p. 226, 1884. 
Three valves, Station 307, east of George’s Bank, in 980 fathoms. Frag- 
ments, Station 325, off Cape Fear, N. C., in 647 fathoms. Two valves, Sta- 
tion 340, south of Martha’s Vineyard, in 1,394 fathoms. One dead, Station 
341, south of Martha’s Vineyard, in 1,241 fathoms. 
