310 BULLETIN OF THE 



Bushia elegans, n. s. 



Shell white, thin, inequilateral, the left valve a little the smaller, and the 

 basal edge of the right valve projecting beyond the other ; apices of the beaks 

 touching each other; shell posteriorly sharply truncate; anterior part of the 

 shell forming sixteen twenty-fifths of the whole length ; the anterior margin 

 rather pointedly rounded, and the extreme anterior point nearer to the level 

 of the base than to that of the hinge-line; beaks not much elevated but mod- 

 erately full; the surface evenly concentrically deeply grooved all over, about 

 three interspaces to the millimeter, the grooves narrower than the interspaces ; 

 a short external ligament behind the contiguous beaks; a keel extends from 

 the beak to the upper posterior angle of the truncation of the posterior side 

 (which is almost as abrupt as in Mya truncatu) parallel with the descend- 

 ing hinge-margin ; over this keel the raised interspaces form threadlike ribs; 

 within the keel is a narrow nearly smooth lanceolate depressed area, wider in 

 the left than in the right valve; the angle at the end of the keel where the 

 truncation begins is abrupt ; the basal angle is very bluntly rounded; interior 

 smooth, with some radiating stria;; the beak, inside its tip, is filled with a 

 dolid transparent deposit, on which the feet of the arched ossicle are' attached 

 by a layer of cartilage ; the hinge is toothless, thin, and weak; the imprint of 

 the mantle invisible; but the pallial sinus is moderately deep and rounded; 

 there is no visible epidermis; the surface is smooth, but not brilliant; the 

 posterior hinge-margin, looked at from above, is seen to be somewhat flexuous 

 laterally. Lon. of shell 12.5; alt. 10.0; diameter 6.0 mm. 



Habitat. Station 272, near Barbados, in 76 fms., hard sand, bottom tem- 

 perature 64°.75 F. (one right valve). U. S. Fish Commission, Station 2639, 

 56 fms., in the Straits of Florida, one living specimen and one valve. 



The possession of a living specimen in a good state of preservation has en- 

 abled me to fix the position of this elegant little shell, which from only the 

 single valve obtained by the " Blake " would have been a little doubtful. 



The soft parts (in alcohol) afford the following notes. Siphons not very 

 long, entirely separated ; mantle closed, except in front of the foot ; ends of 

 both siphons papillose ; mantle simple, smooth along the edge ; gills large, 

 lamellse dorsally much crumpled, both sides united at the tips behind ; palpi 

 very small, narrow ; foot small, rather hatchet-shaped, not grooved behind ; 

 posterior adductor the larger ; the inner gill on each side much the shorter 

 and narrower of the two ; the gills together envelop the whole body except 

 the foot and a passage-way to the excurrent siphon. The ossicle forms a 

 U-shaped arch, its feet a little enlarged and divaricating backward ; the hinge 

 margin is normally entire; but, with the ossicle in place, it is impossible to 

 separate the valves without breaking a little notch, just below the beak where 

 the ossicle crosses, in the valve which does not retain the ossicle, or in both ; 

 the outer surfaces of the mantle and the soft parts in general, except the liver, 

 are not pigmented. 



