DALL: MOLLUSCA AND BRACHIOPODA. 375 
lete toward the ends of the shell; near the base are five close concentric striae 
which extend the length of the margin, decidedly finer than the ripples; interior 
polished, margins entire, pallial sinus distinct; hinge with about fifteen anterior 
and thirteen posterior teeth, separated by an inconspicuous chondrophore. 
Length of shell, 6.2. ; of anterior end, 3.0; alt. 3.8; max. diam. 3.0 mm. 
U.S. 8. “Albatross,” station 2799, Panama Bay, in 294 fathoms, mud. U.S. 
N. Mus. 110,690. Also at stations 2794, in 62 fathoms, sand, bottom temperature 
59°.5 F.; 2801, in 14, and 2803 in 26 fathoms, mud. 
The sculpture variesgin strength a good deal for so small a shell; occasionally 
the concentric sculpture covers the whole of the valve, and now and then one is 
seen which seems almost wholly smooth. 
Leda (Jupiteria) lobula Datt, n. sp. 
Shell small, olivaceous, slightly inequilateral, rounded at both ends, the anterior 
a little shorter ; anterior dorsal slope slightly convexly arcuate, posterior straight ; 
the beaks, capped with a distinct protoconch, low and nearly vertical; both ends 
rounded, the anterior broader; external sculpture of regular rounded, elevated 
concentric threads with wider intervals, evenly covering the whole disk but 
stronger in the middle of the shell; interior polished, hinge with nine teeth on the 
posterior side of the beaks, and about thirteen on the anterior, the chondrophoric 
pit confined to the hinge line and very inconspicuous. Length, 4.7; alt. 3.2; 
diam. 1.5 mm. 
U.S. 8. “ Albatross ” station, 3422, in 141 fathoms, mud, off Acapulco, Mexico, 
bottom temperature 53°.5. 
This shell may not be fully mature, but as far as now appears it is not the young 
of any of the known species of this region. It is remarkable for its oval shape, 
which if characteristic of the fully adult would hardly allow it to be regarded as 
a member of this section of the genus. 
Leda (Leda) costellata Sowersy. 
Nucula costellata Sowerby, P. Z. S. London, 1832, p. 198; Conch. IIl., Nucula, 
fig. 8; Hanley, Thes. Conch., 3, Mon. Nuculacea, p. 111, pl. 228, fig. 59. 
Gulf of California to Panama. U.S.S. “ Albatross,”’ station 2823, in 26 fath- 
oms, sand. U.S. N. Mus. 96,424. : 
This species, with Z. decora and concinna A. Adams, has a very different as- 
pect from those of the Z. pernula type with which they are associated. 
Leda (Leda) cordyla Datt, n. sp. 
Plate 6, figures 6, 7. 
Shell very small, very inequilateral, rostrate, olive green, strongly concentri- 
cally sculptured; beaks high, pointed, slightly opisthogyrate, showing a small 
