20 Proceedings of the Royal Society of Victoria. 



Desjiiacidon steniderina, Carter sp. 



Halichondria stcllidernia, Carter, A.INI.N.H., December, 1886, 

 p. 451. 



This species is characterised by its thick, lobose and compi'essed, 

 or massively lobulate external form ; with small vents scattered 

 on prominent parts ; soft and spongy texture and pale yellow 

 colour in spirit. The main skeleton is a wide, sub-rectangularly 

 meshed network of stout spicular fibre, containing very many 

 slender spicules. At the surface radiating whisps of the same 

 spicules surround the ends of the primary fibres in a stellate 

 fashion. The megascleres are very slender, straight, smooth 

 strongyla, commonly slightly inflated at the ends, and measuring 

 about 0'18 by 0'0028 mm. The microscleres are thickly scattered 

 through the ground substance and have the form of small triden- 

 tate isochelee with strongly curved shafts and very minute flukes, 

 the vhole resembling a sigma and measuring about O'Ol mm. 

 long. 



E.N. 684 (s. 9) ; 710 (s. 8) ; 947 (s. 9) ; 955 (s. 6) : 967 (s. 6). 



B.M. sp. 29 (" Halichondria stcUiderma, C. Type ;" Reg. 86- 

 12-15-148). 



Desniacidon intermedia, n.sp. 



Subcylindx'ical or slightly compressed, irregularly branched. 

 Main stem up to one inch in diameter, tapering gradually to apex, 

 nearly a foot long ; branches much shorter and slendei'er. 

 Surface smooth and even, minutely reticulate, with thick dermal 

 membrane, harsh to the touch. Vents very small, slightly pro- 

 minent, uniserial or scattered on both margins. Firm, resilient, 

 very tough. Very pale yellow in .spirit, stained purplish on the 

 surface. 



Skeleton, a very irregular, coarse network of stout luultispicular 

 fibre, breaking up at the surface into close-set radiating tufts of 

 oxea, whose shortly projecting points form the dermal reticula- 

 tion. Many oxea are loosely scattered between the fibres, which 

 themselves have no obvious cement. 



Megascleres, rather stout, straight, sub-fusiform oxea, rather 

 abruptly pointed at each end ; measuring about 0"25 by 0*01 mm. 



