184 "ENDEAVOUE" SCIENTIFIC RESULTS. 



(iv.) The special dermal styli are connected by a perfect 

 gradation of forms with the auxiliary styli. Those 

 which stand perpendicularly to the surface are rarely, 

 if ever, more than 150 x 5 ;i in size. The majority of 

 them are provided with a few basal spines which are 

 relatively larger than those of the auxiliary and prin- 

 cipal styli. Unlike the corresponding spicules of 

 R. iypiciis, the dermal styli are here usually quite 

 straight. 



Microscleres. — 



(i) The isochelae palmata? reach a maximum length vary- 

 ing in different specimens from 20 to 24 ;<, whilst in 

 any given specimen there may be a difference of as 

 much as 6 // between the longest and the shortest. 

 The shorter length is usually associated with some 

 degree of curvature of the shaft. The palms when 

 viewed from the front are somewhat triangular in 

 outline, with rounded corners; they are longer than 

 broad. 



(ii.) The toxa are simply angulately curved, and resemble 

 a bent microxea. Size: 55 x 1.7 n up to 75 x 2.5 ii. 

 They are relatively few in number, and are sometimes 

 apparently absent. 



Loc. — Port Jackson (Austr. Mus. Coll. ; ten specimens). 



RHAPHIDOPHLI^S PAUCISPINUS, Vlll'. MLLTIPOKIS, IJliiteleggc . 



(Plate xx\-., fig. 2.) 



This variety differs from the typical form in its elongately 

 branched habit and the somewhat greater size of its megas- 

 cleres. All the specimens so far obtained are stipitate. The 

 branches are given off in one plane, and may or may not 

 anastomose. The specimen originally figured does not give a 

 correct idea of the usual form of the sponge, owing to the 

 fact that in it the branches, either through growth in a con- 

 fined space or as a result of drying are bunched together. A 

 specimen obtained by the "Endea\our" (Plate xxv., fig. 2) is 

 peculiar in the wide separation of its branches. W'hitelegge's 

 statement of the spicule-dimensions stands in need of correc- 

 tion ; their maximum values are as follows : — 



Megascleres. — 



(i.) Principal styli, 300-360 x 12-16 fi. 



(ii.) Acanthostyles, 90-105 x 8-9 f«. 



(iii.) Auxiliary styli, 300-360 x 8-10 (rarely more than q) /(. 



(iv.) Special dermal styli, rarely more than 160 x 6;/. 



