254 Proceedings of the Royal Society of Victoria. 



cleres are tylostyli, measuring about 0-44 by O01 mm. and the 

 microscleres very robust spirasters of the ordinary form, by no 

 means confined to the surface of the sponge but densely crowded 

 throughout, intermingled with slenderer and probably young 

 forms of the same. The spirasters measure about O044 by 

 033 mm. (including the spines) when fully grown. This species 

 is certainly nearly related to Schmidt's S. cunctatrix. 



R.N. 432 (x, 19 f.; "cadmium-orange"); 592 (x, 19 f.j "poppy- 

 red, shading to buff below"); 107S (x A). 



B.AI. d. 121 ("Spristrella cunctatrix var. robusta." Reg. 86-12- 

 15-353). 



Spirastrella fibrosa, n. sp. 



Sponge sessile, massively lobose or irregularly rounded, or 

 tongue-shaped with narrow margin. Surface subglabrous, 

 minutely reticulate in parts, almost smooth or faintly conulose, 

 nodular or warty. Vents usually small but prominent, grouped 

 on upper parts, sometimes on small, conical, thin-walled projec- 

 tions. There may be a distinct cortex, but this appears to 

 depend upon the state of growth. Texture firm, compact (but 

 with large exhalant canals), corky, resilient. Colour in spii'it 

 pale yellow or white. 



Skeleton. The main skeleton is an irregular and very wide- 

 meshed reticulation of stout, dense, compact spicular fibre. 

 The main lines of this fibre are about - 36 mm. thick, and are 

 but sparingly interconnected by secondary lines in the deeper 

 parts of the sponge. As it approaches the surface, however, each 

 main fibre gives sives ff numerous slender branches at different 

 levels and these subdivide again and again until they end in 

 brushes of radiating spicules whose apices, intermingled with 

 abundant asters, sometimes from a definite dermal reticulation, 

 and sometimes merely a rather scanty armature of slightly 

 projecting points. There is no visible spongin and, although the 

 megascleres are mostly collected in the stout multispicular fibres 

 of the main skeleton, yet many of them are irregularly scattered 

 in the intervening ground-tissue. 



Megascleres. Straight, slender styli, evenly rounded or very 

 slightly inflated at the base and gradually and sharply pointed at 

 the apex; of very uniform shape and size, measuring about 0*33 

 by 007 mm. 



