MUSEUM OF COMPARATIVE ZOOLOGY. 317 



Family SAXICAVID.E. 

 Genus SAXICAVA Fleurian de Bellevob. 



Saxicava azaria Dall. 



Saxlcava azaria Dall, Bull. M. C. Z., IX. p. 116, 1881. 



Plate IV. Figs. 9 a, 9 b. 



Habitat. Off Charlotte Harbor, Fla., 13 fms.; Station 39, Gulf of Mexico 

 sixteen miles north of the Jolbos Islands, in 14 fnis. 



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 Avith 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. 



Family i^HOLADID.E. 



Genus XYLOPHAGA Tcrton. 



Xylophaga abyssorum, n. s. 



Plate IX. Figs. 7, 7 a. 



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°. F. 



