122 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 8i 



Description. — Shape, massive. Size, 4 by 7 by 12 cm. Consist- 

 ency, spongy. Color in life, slaty ectosome over drab ectosome. As 

 collected the sponge appeared lipstomous on account of the closure 

 of apertures, and even in the aquarium the sphincters did not relax. 

 It would seem that both pores and oscules must be less than 100/x 

 when open. Surface, profusely conulose, the conules less than 1 mm 



high and about 1 mm 

 >:JS^^ "TSiV* apart, apex to apex. 



Ectosomal speciali- 

 zation, an organic 

 dermis not readily 

 detachable, opaque 

 and melanistic ; this 

 from 300/x to 700/x 

 thick. Endosomal 

 structure, a flesh 

 packed with spheroi- 

 dal flagellate cham- 

 bers about 25/i, to 30/x 

 in diameter, and also 

 containing rather nu- 

 merous evenly dis- 

 tributed foreign spic- 

 ules and fragments 

 of spicules, a little 

 sand, and other de- 

 bris. The skeleton 

 is a reticulation 

 chiefly of solid second- 

 ary fibers 60ju, to 200/x, 

 in diameter. The 

 spongin is rathe r 

 granular-surfaced 

 and medium dark 

 brown, very like that in the commercial sponges. The fibers are often 

 contorted, but the meshes are usually rectangular, about 200/i, to 500/x 

 in diameter. Here and there through the reticulation are principal 

 fibers ascending perpendicularly to the surface. These are recogniz- 

 able by having slight, scattered content of coring spicule fragments, 

 but more so by somewhat fasciculated or fenestrated architecture. 



Remarks. — With some hesitation this species is here described in 

 the genus Spongia., from typical members of which it differs sharply 

 by having semifasciculated principal fibers. It agrees closely with 

 Spongia in most or all other points, and this genus may well be 

 employed pending revision of the horny sponges. 



FiGCEK 75. — Spongia idia, new species, x 18, drawn from a 

 section taken perpendicular to the surface. Only the fiber 

 and dermis are drawn, the flesh and foreign intrusions 

 being omitted because their inclusion: would ob.'^cure the 

 structures to be illustrated 



