164 STELOSPONGIA. 



The canal-system is rather remarkable. The inhalant pores lead into a 

 somewhat complicated system of tangeutially extending, irregular canals with 

 annnlar strictures ; these finally open out into very wide, taugentially ex- 

 tending, irregularly cylindrical canals, which measure on an average 1 millim. 

 in width. The narrow inhalants proper arise from these wide canals. The 

 ciliated chambers are 0-041 millim. wide, regularly spherical, and provided 

 with very short special efferents or opening directly into the wider exhalants. 



Our sponge shows in many respects great affinity to Holme ; it connects the 

 genera Halme and Stelospongia both in respect to the large size of the sub- 

 dermal canals, which might be regarded as vestibules, and in the structure of 

 the skeleton. 



G-EOGBAPHiCAL DISTRIBUTION. — New Zealand : Port Chalmers {Parker). 



Stelospongia mirabilis, n. sp. 



Irregularly massive sponges which attain a maximum diameter of 70 millim. 



The skeleton is composed of flabelliform trelliswork-like bands 6 millim. 

 broad. These consist of numerous main fibres 0*2 millim. thick, which are 

 charged with fairly abundant foreign bodies. The connecting-fibres are very 

 short and quite simple; they join adjacent main fibres, are 0- 1-0- 16 millim. 

 thick, and contain hardly any foreign bodies. 



GrEOGBAPHicAL DISTRIBUTION. — South coast of Australia : Port Phillip, V. 

 (Lendenfeld). East coast of Australia: Port Molle, Q. (Ramsay). 



Stelospongia canalis, n. sp. 



The sponge consists of a number of digitate processes which grow out from 

 a common basal mass. It attains a height of 210 millim. and a breadth of 

 170 millim. The digitate branches are straight and extend obliquely upwards; 

 they are not perpendicular and parallel. These processes are regularly cylindrical 

 in their basal portion, and appear conic, tapering to a narrow end distally. 

 The transverse section is pretty regularly circular throughout. Near their 

 base, where they are thickest, the digitate branches measure 30 millim. near 

 the end, 18 millim. in diameter. On the surface of the skeleton grooves 

 10 millim. deep and about equally wide are observed, which extend regularly 

 longitudinally up the branches, one on each digitate process. On the surface 

 of the massive central part of the sponge these grooves are moi-e irregular, 

 and anastomose here and there. In the living sponge these grooves are 

 covered with a fine membrane. The surface of the living sponge is covered 

 with small broad conuli, 0-5 millim. high, which are on an average 1*5 millim. 

 apart. In the membranes which cover the grooves in the skeleton there are, 

 of course, no conuli. These membranes, which are more or less depressed. 



