172 STELOSPONGIA. 



it is rather roughened by the ascending primary fibres (Polejaeff, loc. at.). 

 I do not quite understand this description. The type-specimens of Polejaeff's 

 Oacospongia levis are nearly smooth, only here and there indications of small 

 conuli are observed in them. The surface of the skeleton is smooth. A circular 

 osculum 8 millim. wide is situated close to the summit of each marginal 

 process. 



The dry skeleton is dark brown, pretty hard, slightly compressible and 

 elastic. According to Polejaeff, the outer surface of spirit-specimens is black, 

 and the interior yellowish grey. 



The skeleton consists of cylindrical or slightly compressed fascicles, 1 millim. 

 thick and on an average 1*5 millim. apart. The main fibres in the fascicles 

 are 0*24 millim. thick, cored with abundant spicule-fragments, 0*12 millim. 

 apart, and joined by short transverse fibres 0-06 millim. thick. The meshes 

 in the fascicles are square, with rounded corners ; 0-4-0-6 millim. wide. The 

 connecting-fibres are gracefully curved and very uniformly 0-04 millim. thick ; 

 the meshes betw-een them are irregular and 1 millim. wide. 



The specimens from the deep water off Barra Grande, described by Polejaeff 

 {loc. cit.) as Cacospongia levis, which is one of the only three horny sponges 

 which have been procured from depths exceeding 250 fathoms, are in every 

 respect identical with some of the numerous specimens of this variety dredged 

 by me in shallow water on the Australian coast. 



Geographical Disteibution. — South Atlantic Ocean : off Barra Grande 

 (' Challenger '). 



North coast of Australia: Northern Territory, S. A. (Haache). "West coast 

 of Austi-alia : Freemantle, "W. A. {Boiverhank Coll.). South coast of Australia : 

 Port Phillip, V. (Lcndenfeld). East coast of Australia : Swan River, Q. (British 

 Museum Coll.). 



Stelospongia australis, var. conulissima, Hyatt. 



Stelospongia friahilis, A. Hyatt, "Revision of the North American Poriferse. — 

 Part II.," Memoirs of the Boston Society, vol. ii. p. 530 (1877). 



Small, horizontally extended, incrusting sponges, which are only 14-18 

 millim. high. The surface is covered with conuli, 4 millim. high and 3 milhm. 

 apart. In the skeleton projecting band-shaped fascicles of main fibres are 

 observed on the surface, which are 4 millim. long, 2*5 millim. broad, and 0*2 

 millim. thick ; these are about 3 millim. apart, and stand in irregular longi- 

 tudinal rows. On the upper surface one or a few oscula, 8-10 millim. wide, 

 are observed, surrounded in the skeleton by frills of fibre-fascicles. 



The dry skeleton is dirty dark brown, stiff, but compressible, and pretty 

 elastic. 



