2::8 



'ENDEAVOUR" SCIENTIFIC RESULTS. 



Spicules. Scarce auxiliary spicules are scattered inter- 

 stitially. Megascleres :■ — (i.) Principal siyli, usually more 

 or less curved, sub-fusiform, with a slight sub-basal 

 waist, varying in length from about ^o {seldom less than 

 80) to 155 }i, and in diameter up to 5.5 m {ii.) auxiliary 

 tylostyli, straight or in variable manner curved, 100 {or 

 less) to 250 ^ in length, and rarely as much as 1.5 }i in 

 diameter. Microscleres : — Toxa, by no means scarce, jo 

 to 80 }i in length and never more than i ]i in diameter. 



The external form of this 

 species has already been suffi- 

 ciently well described, but no 

 adequate account of the skeleton 

 has so far been rendered ; also, 

 the information concerning the 

 spicules is incomplete, and, to 

 some extent, misleading. The 

 specimen herein figured measures 

 100 mm. in height. The skeleton 

 is a very regular reticulation of 

 densely horny fibres, which are of 

 a pale brownish tint and (except in 

 proximity to the sponge-surface) 

 rarely less than 70 or more than 

 100 ]i in diameter ; the main fibres 

 contain a meagre wispy core of 

 slender styli, the connecting fibres 

 are vacant. As seen in median 

 longitudinal section of a branch, 

 the main fibres run longitudinally 

 (in subparallelism, and from 80 to 

 120 ]i apart) with a slight outward 

 trend which gradually increases 

 to a curvature as the exterior is 

 approached, and arrive at the 

 surface at an inclination to it 

 \arying (in different parts of the 

 sponge) from about 45° to nearly 

 90° ; they are joined at irregular 

 intervals, in a scalariform fashion, 

 by the short, stout transverse 

 fibres. The meshes of the 

 reticulation have their angles 

 rounded off, and are usually elongated in the longitudinal 

 direction ; they vary in shape from circular to oblong. 

 Owing to the absence of a dermal membrane, the free ex- 

 tremities of the main fibres give to the surface an appearance 

 of hispidity. 



Fig. 54 — O. subliispida. a 

 Principal styli. b Auxiliary 

 tylostylus. c Toxa. 



