280 Mr. A. Dendj on a new Species o/Cladorhiza. 



Cladorhiza pentacrinus, n. sp. 



Sponge (PI. XV. fig. 1) stipitate, consisting of a long, 

 slender stem, terminating above in a subglobular body, which 

 bears a circlet of short pinnaj or arms *, curving upwards and 

 inwards over the top. The stem terminates below in a num- 

 ber of very slender, long, branching rootlets. Total length 

 of the single specimen 24 millim. Length of body and pinnae 

 together 4 millim. Length of stem 11 millim. Diameter of 

 body 2 millim. Surface of body and pinnse hispid, owing to 

 the projection of some of the megasclera. Colour white.. 

 Oscula and pores unknown. 



Skeleton. — The skeleton is arranged much as usual in the 

 genus CladorMza. The skeleton of the stem is formed of 

 long, slender styli, arranged side by side longitudinally ; in 

 the head it breaks up into several radiating branches, one for 

 each pinna. In the basal part of the head these branches 

 are not very well defined, and the spicules composing them 

 are ratlier loosely arranged. Although the pinnas are curved 

 the spicules forming their axes are straight, and hence it 

 follows that the styli in any part are inclined at an angle to 

 those lower down in the pinna (PL XV. fig. 2). The root- 

 lets are formed by repeated dichotomous ramification of the 

 stem. The styli are smaller in the head and pinnas than in 

 the stem, and they also become much smaller and slenderer 

 in the rootlets as ramification proceeds, the extreme end of 

 each rootlet being composed of a single long and very slender 

 spicule (PI. XV. figs. 3, 5). They are arranged throughout 

 with their apices pointing upwards. 



Sjncules. — (a) Megasclera : These are the usual long, 

 slender, fusiform styli (PI. XV. figs. 4, 5) ; they are frequently 

 blunted at the apices, and in full-grown examples they are 

 narrowed at the base. They vary greatly in size, measuring 

 when full-grown (in the uppermost part of the stem) about 

 I'O by 0'02 millim. They are smaller in the head and arms 

 and in the rootlets. The terminal spicules of the latter 

 measure only about 0"0063 millim. in diameter, and they 

 have faintly developed oval heads, forming the extreme 

 points of the rootlets. 



(Ij) Microsciera : These are of two kinds : (1) tridentate 

 anisochela3 (PI. XV. figs. 6, 7, 8), of the ordinary general 

 Cladorhiza form, but with a well-marked specific character. 

 The three teeth at the large end are of considerable size, and 

 the shaft is curved and fimbriated as usual in the genus. The 



* I am unable to give the exact number of the arms, but there are about 

 ten or twelve. .Judging from the allied Cri/iorhiza forms, I am inclined 

 to attach no great importance to the exact number. 



