SILICIOUS AND HOENY SPONGES WILSON. 395 



four oscula, all at the ends of short oscular lobes or prominences. 

 A third specimen, broken, from station D5447, resembles the latter 

 in respect to the oscula. Color, light yellowish brown. 



The dermal membrane is the usual sieve membrane, perforated 

 everywhere by closely set pores. It is, where perfect, well lifted 

 up above the subjacent tissue, as if the sponges had been killed when 

 thoroughly expanded. Beneath it narrow trabeculae of denser tissue 

 are rather vaguely seen. If now the dermal membrane should sink 

 down, in a sponge losing water, upon the trabeculae, the effect of 

 a reticulum, formed by the trabeculae and embracing pore areas, 

 would be produced. Bowerbank (1866, p. 230) refers to this ap- 

 pearance of the surface in dried specimens. Tangential, narrow 

 subdermal canals are present in some abundance but they are not 

 conspicuous. Doubtless with respect to them, also, the physiological 

 state of the sponge (contracted or expanded) would materially 

 alter the appearance of the surface. 



The spicules of the interior are thickly strewn in all directions in 

 the usual irregular way. Tracts, as distinct from the general mass 

 of spicules, are not recognizable. In the ectosomal trabeculae be- 

 tween the subdermal chambers, the spicules have in general a radial 

 or obliquely radial position and project. Such aggregations of spic- 

 ules are however often too wide and not compact enough to be 

 called tracts. The dermal membrane contains, in addition, abun- 

 dant more or less tangential spicules. The oxea is the usual smooth, 

 slightly curved form, tapering evenly to sharp points, 700-900 by 

 26-32 [jl with smaller sizes. Now and then a style occurs. 



The species, as generally conceived, is cosmopolitan, of no particu- 

 lar habitus, and without any very marked characteristics. The 

 oxeas are always relatively long and slender; Ridley and Dendy 

 (1887, p. 3) put the range in length at 200-1000 [x, Lundbeck (1902, 

 p. 7) at 350-1000 [/.. The spicules are especially large in the Indo- 

 Pacific specimens (Topsent 1901, p. 10). The species has in recent 

 years been recorded several times from this region by Dendy (1905, 

 p. 146; 19166, p. 112; 19215, p. 37). 



The spicules of the interior are characteristically strewn without 

 order and thickly; those of the dermal membrane may be closely 

 packed in all directions, some tangential, some radial and projecting, 

 others oblique; but often the dermal spicules are so arranged as to 

 form a rete with 3 to many sided meshes (Bowerbank, 1866, p. 229; 

 Lundbeck, 1902, p. 17; Dendy, 1905, p. 146). Since the spicules are 

 free to move, the difference in arrangement of the dermal spicules 

 may possibly be correlated with the physiological state of the sponge. 

 Sponges are included in the species, in which the spicules of the in- 

 terior show a strong tendency to arrange themselves in coarse fibers 



