256 Proceedings of the Royal Society of Victoria. 



seen to occupy each the centre of such an areola. Where the 

 surface is much contracted the polygonal outlines between the 

 areola? became much less distinct, and the surface may even 

 appear simply warty. The inhalant pores appear to be located 

 in the slight elevations which occupy the centres of the areola? 

 over the general surface ; the vents occupy the apices of similar 

 though more pronounced elevations on the margin of the sponge, 

 a condition which reminds one somewhat of the arrangement in 

 some species of Latrunculia. 



There is a dense cortex 1 mm. thick or more. The texture in 

 spirit is very compact and corky, but slightly compressible and 

 resilient, and with large exhalant canals. A little very stout, 

 anastomosing fibre may be visible to the naked eye in the 

 interior. Colour in spirit pale dull yellow throughout. The dry 

 specimen is very hard, tough and incompressible, and of a pale 

 "sponge brown" colour. 



Skeleton. The main skeleton is a very sparse and irregular 

 network of very stout, ill-defined fibres or tracts of densely 

 agglomerated megascleres. The very wide spaces intervening 

 between these tracts are rather sparingly occupied by loosely and 

 irregularly scattered megascleres. The cortical skeleton is very 

 dense, the deeper part consists of megascleres lying confusedly in 

 every position, in the more superficial part the megascleres are 

 arranged more or less at right angles to the surface. Sometimes 

 the lines of demarcation between the adjacent areola? appear to 

 be continued right through the cortex, as shown in vertical 

 section by the peculiar arrangement of the megascleres, which 

 diverge from the dividing plane like hair at the parting. 



Megascleres; slender, slightly curved tylostyli, with well- 

 developed heads inflated at a short distance from the base as in 

 many species of Suberites ; apex varying from bluntly rounded to 

 sharp-pointed ; size about 04 by O006 mm.; perhaps a trifle 

 shorter in the outer part of the cortex, while in the deeper parts 

 numerous long slender hair-like forms, with relatively large 

 heads, occur amongst the ordinary ones, of which they are 

 probably simply young individuals. 



Microscleres ; of two chief forms, both doubtless modifications 

 of the spiraster ; (a) short, straight, rod-like, thickly covered 

 with small spines and blunt at the extremities ; size about - 015 



