MUSEUM OF COMPARATIVE ZOOLOGY. al7 
Fay SAXICAVIDA. 
Genus SAXICAVA Fteurian DE BELLEVUE. 
Saxicava azaria Datt. 
Saxicava azaria Dall, Bull. M. C. Z., IX. p. 116, 1881. 
Plate IV. Figs. 9a, 9 b. 
Habitat. Off Charlotte Harbor, Fla., 13 fms.; Station 39, Gulf of Mexico 
sixteen miles north of the Jolbos Islands, in 14 fms. 
In spite of the variability of this group, I am pretty confident that this is 
not one of the varieties of the northern S. rugosa. The second specimen shows 
the surface more perfectly, and is covered with a closely adherent red-brown 
epidermis under which the shell is finely wrinkled in a manner different from 
any of the ordinary species I have been able to compare with it. 
Famity PHOLADIDA. 
Genus XYLOPHAGA Torrton. 
Xylophaga abyssorum, n. s. 
Plate IX. Figs. 7, Ya. 
Shell minute, wedge-shaped and nearly closed behind, inflated and more than 
half open in front; anterior area concentrically sharply striate, reflected at 
the dorsal edge, and covering in somewhat less than half (on each side) of the 
anterior face of the animal; beaks small, not prominent, but sharply defined, 
giving rise to two somewhat nodulous keels, which extend to the opposite 
edge of the valve, where they are doubled in forming a kidney-shaped callus 
inside the edge; the anterior keel is less prominent than the second one, and 
the space between them is slightly depressed and smooth except for incremental 
lines; there is a narrow smoothish margin with oblique striations between the 
first keel and the hinder edge of the anterior area; this widens out below the 
lower edge of the anterior area and forms a sort of margin to the central keeled 
part of the valves; it is rounded off at the ventral angle formed by the ventral 
and anterior edges; behind the keels the posterior area is roundly arched be- 
hind the two ends of the posterior keel; the surface is concentrically striate, 
but less closely than is the anterior area; the posterior margins close perfectly; 
the shell is pure white, and exhibits no accessory pieces or any place of attach- 
ment for any. Lon. of shell 4.0; alt. 3.0; diam. 4.0 mm. 
Habitat. One specimen in soft coral nodule at Station 215, in 226 fms., 
off Santa Lucia, bottom temperature 51°.0 F. 
