NO. 2183. NEW NORTHWEST AMERICAN BIVALVES— BALL. 397 



LEDA FUSCONA, new species. 



Shell small, subtriangular, rounded, thin, dull ohve, the anterior 

 slightly shorter than the posterior end, the base arouate; the posterior 

 end attenuated, compressed, pointed; sculpture of fine concentric 

 threads, close set and covering the anterior two-thirds of the valves, 

 stopping abruptly at the posterior third where the compression 

 begins; beaks not prominent, a small and narrow lunule and escutch- 

 eon indicated; hinge with 8 anterior and about 4 posterior teeth, 

 the resilifer small, subumbonal, not projecting. Length, 4; height, 

 2.7; diameter, 1.7 mm. Cat. No. 215597, U.S.N.M. 



Station 2923, off San Diego, in 822 fathoms, mud. 



LEDA PHENAXIA, new species. 



Shell small, sohd, plump, smooth except for faintly evident incre- 

 mental hues and dehcate radial striulae; periostracum dark ohve, 

 immediately under the beaks blackish for a short distance; base 

 evenly arcuate, dorsal slopes nearly straight; beaks nearer the ante- 

 rior end, full, not pointed, with a short-cordate lunular impression and 

 narrow, elongate escutcheon, neither defined by any sharp boundary; 

 hinge very strong for the size of the shell, with about 8 or 9 long teeth 

 on each side of a rather small strong resihfer. Length, 4.5; height, 

 3.5; diameter, 1.3 mm. Cat. No. 215596, U.S.N.M. 



Station 2923, off San Diego, CaUfomia, 822 fathoms, mud. 



The short blackish patch of periostracum directly between the 

 beaks gives this little shell the aspect of a Tindaria, and the strong 

 hinge makes the shell very difficult to open, but the hgament is 

 strictly internal. 



LEDA SPARGANA, new species. 



Shell small, elongate, inequilateral, pale olivaceous, compressed; 

 prodissoconch conspicuous, otherwise the beaks are low, and about 

 4 mm. from the anterior end of the shell; sculpture of low concentric 

 ridges, stronger anteriorly, sparser toward the beaks, and obsolete on 

 the dorsal area behind; there is an obscure radial depression ante- 

 riorly, and two obscure radial ridges on each side of the impressed 

 escutcheon where the dorsal margin of the valves is prominently ele- 

 vated; there are about 12 anterior and 18 posterior teeth, the resihfer 

 is small, rotund, and subumbonal; there is a small mesial ridge near 

 the end of the rostrum internally. Length, 12; height, 5; diameter, 

 2.6 mm. Cat. No. 208897, U.S.N.M. 



Station 4367, off Point Loma, San Diego County, California, in 215 

 fathoms, mud. 



LEDA HAMATA Carpenter, 1864. 



Variety limata Dall. In this variety the valves have the same pro- 

 file as in the typical form but the strong concentric sculpture, which is 

 so uniform in the northern specimens of this species, is subject to 



