102 ProceediiKjs of the Royal Societi/ of Victoria. 



till' ;n)ii'al luy long, slender, .straight and graduall}' sliarp- 

 ])ointed, nearly in a line with the basal ray ; the facial rays 

 short, stout, conical and sharp-pointed, the basal rather 

 longer than the other two and often slightly crooked, the 

 orals being straight; basal vav about 003 by 0007 mm. ; 

 orals 002'by 0007 mm. ; apical 008 (or le.ss) by 0000 mm. 

 These spicules are found in the walls of the larger exhalant 

 canals, but they are not very abundant. (2) Enoi-mous 

 sub-regular or ii-i-egular triradiates, with conical, gradually 

 shar})-pointed rays which measure, when fully developed, 

 about ] -8 by 0-16 nun. These spicules form the bulk of the 

 skeleton and are irregularly and abundantly scattered 

 throughout the thickness of tlie sponge ; they vary con- 

 siderably in size. (3) Small, straigiit oxea, of hair-like 

 fineness and up to about O'l mm. in length ; scattered 

 through the interior of the sponge, either separately or in 

 dense sheaves (trichodragmata). (4) Triradiates of the 

 dermal cortex ; strongly sagittal, with long, nearly straight, 

 very widely extended, gradually sharp-pointed oral rays, 

 and much shorter, straight, gradually sharp-pointed basal 

 ray ; these spicules form a dense feltwork, the\^ are quite 

 irregularly arranged, excejjt that they all lie parallel to the 

 dermal surface. They vary greatly in size, the oi-al rays, 

 which are extended almost in a line, measuring up to about 

 O-tio by 0-()3G mm., with the basal about 0-3 by 0036 mm. 

 (5) Dermal oxea ; straight, .slender, gradually sharp-pointed 

 at each end. In most parts of the surface these spicules 

 are comparatively few in number, projecting at right angles 

 from the dermal cortex and measuring only about O'-t- by 

 O'Ol mm. They viivy greatly in size, hovvevei", and around 

 the margins of the sponge they become very greatly elong- 

 ated, forming a thick, den.se fringe. 



This veiy remarkable species is obviously very closely 

 i-elated to the European Leucandra nivea, as described by 

 Hfeckel in " Die Kalkschwamme " ; in both we find colossal 

 triradiates, smaller dermal triradiates, dagger-shaped quadri- 

 radiates and trichodragmata (which ai-e extremely rare in 

 calcareous .sponges), and in botli we meet with the character- 

 istic encrusting habit. There are, however, certain marked 

 differences in spiculation, as in the shape of the dermal 

 triradiates and of the dagger-shaped quadradiates, and 

 especially in the presence in L. gladiator of the projecting 

 dei'mal oxea, which seem to be entirely wanting in 

 L. inrea. 



