376 bulletin: museum of comparative zoology. 



glassy prodissoconch ; lunular depression striated, lanceolate, not circumscribed ; 

 escutcheon long, lanceolate, striated, the valve margins a little elevated, the area 

 strongly impressed, bounded on each side by two flattened rays, separated by 

 a feeble depression, extending from the beaks to the end of the rostrum, and 

 crossed by a series of small, distant, evenly equally spaced, elevated lamellae ; 

 body of the shell swollen, the rostrum compressed ; anterior end very short ; 

 sculpture of concentric, narrow, rounded ridges with wider channelled interspaces, 

 about twenty-five between the beaks and the base ; general form as figured. Lon. of 

 shell, 8.5; of beaks behind the anterior end, 2.5; alt. 4.0; diam. 2.5 mm. 



U. S. S. "Albatross," station 3354, Gulf of Panama, in 322 fathoms, mud, 

 bottom temperature 46° F. U. S. N. Mus. 122,915. Also at station 2792, off 

 Manta, Ecuador, in 401 fathoms, mud, temperature 42°. 9. 



There are fourteen anterior and about nineteen posterior very small and close-set 

 teeth on the hinge line, the two series separated by a very small and inconspicuous 

 chondrophore. The interior is brilliantly glossy, translucent, and with a low 

 longitudinal ridge dividing the channel of the rostrum. The most nearly related 

 species, from which this is sufficiently distinct, is Leda hamata Carpenter, of the 

 coast of California. 



Leda (Leda) loshka Dall, n. ep. 



Plate 17, figure 2. 



Shell thin, olivaceous, paler toward the um bones, very inequilateral, polished, 

 the disk oval, the posterior end produced in a long rostrum ; beaks low, the pro- 

 dissoconch not differentiated ; lunule impressed, very narrow, lanceolate, bounded 

 by a low but sharp carina ; escutcheon narrow, impressed, striated, very long, 

 extending from the beaks to the end of the rostrum, the valve margins more 

 or less prominent ; the area is bounded by two obscure flattish ribs, the lower 

 wider, separated by a narrow furrow and extended to the end of the rostrum ; 

 disk apparently smooth, but under a lens showing fine concentric and a few 

 irregular faint radial striations ; dorsum and base gradually attenuated, the ros- 

 trum not separated by any marked constriction near its origin; interior glassy, 

 the rostrum with an internal keel corresponding to the external furrow ; resiliura 

 very small, wiioUy internal, obliquely directed backward; hinge with about fifteen 

 anterior and twenty-two posterior very small, short, angularly folded teeth. Lon. of 

 shell, 16.2; of beaks behind anterior end, 5.0; alt. 6.5; diam. 3.0 mm. The 

 teeth were counted on a valve 13 mm. long. 



U. S. S. "Albatross," station 3392, Gulf of Panama, in 1270 fathoms, hard 

 bottom, temperature 360.4 F. U. S. N. Mus. 122,916. 



The most nearly related species is Leda cestrota Dall, from the Atlantic, which 

 is a much larger form with a recurved rostrum. 



Leda (Leda) rhytida Dall, n. ep. 

 Shell small, elongate-ovate, slightly inequilateral, translucent white, covered 

 with a pale olive-gray pcriostracum ; beaks low, adjacent, lunule and escutcheon 



