1132 A MONOGRAPH OP THE AUSTRALIAN SPONGES, 



nearly as wide as the body. Narrower in the oval Sponges it i* 

 relatively much wider in the cylindrical specimens. The body 

 wall is only 2-4 mm. thick, so that the Gastral cavity appears 

 very roomy. The Osculum is destitute of a frill. Our Sponge 

 seems always to be solitary. The outer surface is covered by 

 dense hair protruding a good distance and consequently makes 

 the impression of a thick fur. The inner surface is slightly 

 rough. The cana system, in difierent parts of the Sponge near 

 the Osculum, extremely simple, no lacunes or anastomoses of an}' 

 kind are formed. The body wall is consequently very thin in 

 this part 2 mm. Further down towards the aboral pole we find 

 the Grastral wall perforated by large, densely scattered round 

 holes measuring 1 •5-2-5 mm. in diameter. These exhalent pores 

 lead into longitudinal canals of an oval, transverse section similar 

 to those described in a very difi'erent species, Leucandra mean- 

 drina by myself. The pores or rather short radial canals 

 connecting the longitudinal tubes with Qastral cavity are conic or 

 trumpet-shaped, wide at the mouth, they open with an aperture 

 not exceeding 0-5 mm. in diameter into the tubes. These 

 longitudinal tubes are clothed with the same skeleton as the 

 stomach. 



Spicules : Gastric Quadriradiate spicules. Centripetal, sagit- 

 tally differentiated ray, straight, slender, and protruding into 

 the tubes and Gastral cavity. This ray is cylindrical and pointed, 

 rarely slightly curved towards the end, measuring 0*2 — 0*55 mm. 

 X 0*01 mm. Three tangental rays equal, in a plane vertical to 

 the centripetal ray, straight, conic and pointed with equal angles 

 between them. These rays measure 028 x 001 mm. Triradiates 

 and Quadriradiates of the Parenchyma. Eegular Triradiates 

 with straight conic and rounded rays, measuring 0*35 x 0'02 mm. 

 are predominant in the body wall. Besides there are triradiates 

 of a similar size as the former with curved rays and more or less 

 irregular angles. I have never met with proper sagittal 

 Triradiates. On these irregular spicules and also on a few 

 regular ones an incipient fourth ray can be observed. These 

 forms lead up to Quadriradiates with conic, curved and terminally 

 rounded rays measuring 0-3 x 0-018 mm. which are however 



