MUSEUM OF COMPARATIVE ZOOLOGY. Qi 
Famity VENERIDZ. 
Genus CYTHEREA Lamarck. 
Subgenus DIONE Mecerie vy. MuHLFELDT. 
Cytherea (Dione) hebrza Lamarck. 
Cytherea hebrea Lamarck, An. s. Vert., VI. p. 308, 1818. 
Habitat. West of Florida 30 fms.; off Gordon Key 68 fms.; Barbados, 
100 fms. 
These specimens are all very young, and yet seem to show the characters of 
this species sufficiently. Most of them show traces, outside of the smooth 
colored surface, of a chalky layer which is very soon worn off and leaves no 
trace in the adult. 
Cytherea (Dione) albida Gme tin. 
Dione albida Reeve, Conch. Icon. Dione, pl. x. fig. 39. 
A number of very small and immature valves, dredged at Stations 247 and 
262, near Grenada, in 92-170 fms., may belong to this or some allied species, 
They are not in a condition to be accurately determined. 
Cytherea (Veneriglossa) vesica, n. s. 
Shell thin, inflated, rounded ovate, white, uniformly concentrically grooved, 
polished; no differentiated dorsal area; lunule wide, short, marked by a fine 
inscribed line; beaks tumid, involved, as in Isocardia, twisted away from the 
hinge-line so that their tips are widely separated; margins thin, simple; hinge 
with the teeth arranged much as in Cytherea Sayana Conrad, but with the 
depressions prolonged into pits, the ends of the teeth sharp and pointed, and 
the ventral margin of the hinge-shelf upturned; ligament long, in a deep 
groove, passing away from the hinge-line under the beaks as in Jsocardia ; 
muscular impressions small, near the margin; pallial line with a shallow 
wide wave just before the posterior adductor scar. Lon. of shell 22.0; alt. 21.0; 
diam. 17.0 mm. 
Habitat. Station 36, 84 fms., in the Gulf of Mexico ; Station 167, near Gua- 
delupe, in 175 fms.; Barbados, 100 fms., by the “Hassler”; all dead valves. 
This is a very singular shell. In the absence of the soft parts I am at a loss 
to place it. If it were not for the slight wave in the pallial line, I should, in 
spite of its Venerid teeth, have placed it in the Isocardiide. The very young 
shells, though more elongated and less tumid, resemble Vesicomya atlantica 
Smith; the adults are more like it on a larger scale. The dentition is alto- 
