122 "ENDEAVOUR" SCIENTIFIC RESULTS. 



(ii.) Elongated spined forms, occurring for the most part 

 only in tfie immediate circumference of the canals, in 

 the walls of which they lie tangentially, loosely 

 scattered in a single layer. It frequently happens that 

 several together are apposed so closely, and in such 

 a way, that they cannot by any means be distinguished 

 from a single large branched spicule. Speaking 

 generally, they are characterised by their slender zig- 

 zag form, and the very evident spiral arrangement of 

 their spines. Their length, which is rather variable, 

 sometimes reaches above 80 ^ ; their diameter rarely 

 exceeds 3 /<. 



Loc. — East coast of Queensland, seven miles east of 

 Double Island Point, 33 fms. ("Endeavour"). 



S. montiformis is probably most nearly related to S. vaiia- 

 bunda, Ridley, and S. tentorioides, Dend}'. The striking 

 resemblance which its elongated zigzag spirasters bear to 

 those of Cliouopsis platei, Thiele, and to certain species of 

 Cliona, not only supports the opinion that Spinistrella, Cliona 

 and Clionopsis are allied genera, but seems also to show that 

 such spirasters are of primitive form. 



Spirastrella pocui.oides, sp. nov. 



(Plate xxi., tig. i, and fig. 22.) 



Sponge sessile, massively cup-shaped. Surface smooth; 

 even, or provided with a few low dome-shaped eleva- 

 tions. The oscula {?) are microscopic circular openings 

 on an average "25 mm. apart. Skeleton semi-diffuse, non- 

 fibrous; spirasters scattered in moderate abundance 

 throughout all parts and forming a cortical layer. Megas- 

 cleres : — Tylostyli of a single kind measuring 560 a' ij p. 

 Microscleres : — Spirasters of a single kind, ^^o x 10 fi. 



The following description is based on a single specimen. 



The sponge is a stout-walled and exceeding thick-bottomed, 

 compressed, sessile cup. Its shape may be conceived as hav- 

 ing been attained by the upgrowth of a broad pillar, in which 

 growth has proceeded most rapidly at the periphery. The 

 surface is very smooth, and generally even; the only inequali- 

 ties are in the form of a few broad, rounded protuberances. 

 The interior of the sponge is free from noticeable cavities, and 

 of very uniform structure throughout. The texture of its 

 internal substance, when dry, is such as might result from the 

 close compression of some finely divided fibrous material ; there 

 is no appearance macroscopically of extended fibres. Owing 

 to the (irmness and density of the superficial layer and the 



