540 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



Quadri radiates of oscular margin (A) strongly sagittal. Basal ray 

 straight, finely pointed, 200-260;u, long and 12j!x thick at base. Paired 

 rays strongly diverging, distinctly thicker than basal ray, obscurely 

 showing double curvature, lQ0-2Q0\i long and 1Q\l thick at base. 



Large oxea of oscular margin similar to those which project from 

 the dermal surface. 



Locality. — Off the north point of Copper Island, Comandorski 

 Islands (Station 4788, 57 fathoms). 



Remarks. — This species resembles Grantia coinoxensis^., but shows 

 some differences, chiefly in the external form and in the spiculation. 



7. ACHRAMORPHA DIOMEDIAE, new species. 



Plate 85, fig. 10. 



The collection contains a single specimen of this new species (Cat. 

 No. 9171, U.S.N.M.). The sponge (pi. 85, fig. 10) is in the form of a 

 thin-walled and slightly curved cylindrical tube about 8 mm. long, 

 inferiorly narrowed and swollen in the upper parts, the swelling 

 beginning a little below the osculum. Maximum breadth of body 1^ 

 mm. The terminal osculum leads into the gastral cavity of a habitus 

 corresponding to that of the entire specimen. A feebly developed 

 fringe exists around the osculum. The sponge wall is less than ^ mm. 

 thick. The dermal surface is slightly hispid due to projecting oxas. 

 The gastral surface is also more or less rough on account of the pro- 

 jecting apical rays of gastral quadriradiates. The color is nearly 

 white in alcohol; the texture delicate. 



Structiire. — Both dermal and gastral cortices are very thin. The 

 canal system is of the syconoid type. The flagellate chambers are of 

 an elongate sac-like shape, circular or oval in cross-section with a 

 diameter of 50-150[jl. They extend nearly across the entire thick- 

 ness of wall. Internally they communicate with exhalant canals 

 which run through the gastral cortex before opening into the gastral 

 cavity. The very wide inhalant canals start from beneath the dermal 

 cortex and penetrate deeply into the interspaces between flagellate 

 chambers. 



The dermal skeleton is made up of tangential sagittal triradiates 

 which are loosely distributed in a very thin layer with basal rays 

 pointed downward. The larger oxea are grouped into tufts, with 

 their proximal ends deeply stuck in the chamber layer and the distal 

 ends projecting from the dermal surface. The tubar skeleton con- 

 sists of the basal rays of subgastral triradiates and of the large oxea 

 just mentioned. The gastral skeleton is composed of loosely arranged 

 quadriradiates, lying parallel to the gastral surface in a single or 

 two layers; their basal rays are directed toward the sponge base, 



'^ Grantia comoxensis Lambe, Sponges from the Pacific Coast of Canada. Proc. an'3 

 Trans. Roy. Soe. Canada, 1893, sec. 4, art. 3, pp. 39, 40, figs. 3, a-c. 



