186 STTLOTELLA. 



particularly at the truncate end. They are on an average 0*25 millim. long 

 and 0-004 inillim. thick. 



Geogeaphical Disteibution. — North coast of Australia : Torres Straits {Mac- 

 leay). East coast of Australia : Port Jackson, IN". S. W. {Ramsay, Lendenfeld). 



New Zealand : Nelson {Canterhury Museum, ChristchurcJi, If. Z., Coll.) ; 

 Lyttleton {Haast, Lendenfeld). 



Stylotella polymastia, n. sp. 



(Plate IV. fig. 1.) 



Massive sponges with numerous, irregular, mostly fistular processes arising 

 from the upper surface. The sponge is attached by a broad base and attains a 

 maximum diameter of 300 millim. The oscula are situated terminally on the 

 summits of the processes. 



The sl-eleton consists of a somewhat irregular network of fibres in the central 

 part of the body and of longitudinal fibres in the processes. The fibres 

 are about 0-2 millim. thick, and composed of irregularly situated spicules. 

 The meshes of the skeleton-net are on an average 0-3 millim. wide. Besides 

 these, abundant spicides are scattered irregularly in the ground-substance. 

 The spicules are straight or very slightly curved styli, which attain a length of 

 0*7 millim. and a thickness of 0-22 millim. The pointed end is pretty sharp. 

 The spicule itself appears somewhat fusiform, the thickest portion lies nearer 

 the truncate than the pointed end. Towards the simply rounded truncate end 

 the spicule tapers considerably to about one half of its maximum thickness. 

 Similar smaller and more slender spicules are found together with these in 

 abundance. 



Geogeaphical Disteibution. — East coast of Australia (Ramsay). 



Stylotella rigida, n. sp. 



Erect sponges, attached by a broad base with cylindrical digitate processes, 

 which terminate with rounded dome-shaped ends, on the summits of which the 

 circular oscula are situated. The size of the oscula varies from 1-3 millim. 



The skeleton consists of slightly branched slender fibres, which extend 

 upward and outward in a plumose manner. They are on an average 0*03 

 millim. thick. The meshes between them are 0*2 miUim. wide, and fiUed with 

 dense masses of irregularly scattered spicules. These scattered spicules are so 

 numerous as often to obliterate the fibres altogether. The spicules are straight 

 or slightly curved styli, attaining a length of 0*2 millim. and a thickness of 

 0*006 millim. They are cylindrical, pretty abruptly, but not very sharp-pointed 



