170 STELOSPONGIA. 



(HaacJce) ; Thursday Island, Torres Straits (Lord Stanley). South coast of 

 Australia : King George's Sound, W. A. (Lendenfeld) ; Port Philhp, V. (Leyi- 

 denfeld); Port Phillip Heads, V. (Boston Soc. Coll., B. Wilson); Tasmania 

 (Catten). East coast of Australia : New South Wales (Acad. Philadelpliia 

 Coll.) ; Port Jackson, N, S. W. (Lendenfeld) ; Broughton Island (Ramsay) ; 

 Swan Eiver, Q. (Brown, Jansen). 



New Zealand : Port Chalmers (Parlcer). 



Stelospongia australis, var. fovea, Polejaeff. 



(Plate XI.) 



Cacosponyia amorpha, N. de Polejaeff, Eeport on the Scientific Eesults of 

 the Voyage of H.M.S. ' Challenger,' Zoology, vol. xi. Keratosa, p. 57 

 (1884). 



Regularly radially symmetrical, pyriform, pedunculate sponges, which attain 

 a height of 200 millim. The peduncle is distended below, to form a basal 

 plate by which the sponge is attached, and constricted further up, measuring 

 at the narrowest point about 20 millim. in diameter. It is regularly cylindrical 

 in transverse section, and attains a length of about 25 millim. It widens above, 

 and there is no clear limit between the peduncle and the true body of the 

 sponge— it passes gradually into it. The body of the sponge itself is oval or 

 fusiform, drawn out below to form the peduncle, and above to the slightly raised 

 and large, centrally situated terminal osculum. The body has a regularly cir- 

 cular transverse section, and is in the middle about 80 millim. thick. More 

 irreo'ular or slightly compressed forms occur, but they are very rare. The 

 surface is covered with large and conspicuous conuli, disposed in lines which 

 form a network with very uniform polygonal meshes. In the skeleton this 

 network — hei-e formed by the distal ends of the band-shaped fascicles of main 

 fibres — becomes still more apparent. The concave fields between the ridges 

 are about 3 millim. deep. The conuli are higher in the joining-points of the 

 rido-es than elsewhere, and protrude over the ridges themselves 0-7-l"5 millim. 

 They are smaller and closer together, and the polygonal fields between them 

 less distinct, at the upper and lower ends of the sponge than in the middle. 

 The measurements given above refer to the surface of the central part of the 

 sponge. Longitudinal rows of concave fieds are occasionally more or less 

 fused. Sometimes two or more individuals coalesce to form a polyoscular 

 colony. The oscula are generally situated on the summits of the distal distinct 

 parts of the coalesced individuals, which are rarely fused throughout, in which 

 case the oscula lie in the upper distended margin. The oscula are always 

 surrounded by membranes — frills of longitudinal fascicles of main fibres in the 

 skeleton — which are particularly conspicuous in those colonies which consist 



