SPONGES. 189 



about 25 millims. long and 9 millims. in diameter. Branches about as thick as the 

 stem, slightly flattened, short (usually about 30 millims. long), rather few in number, 

 terminating in abrupt, conical apices. The vents are small openings in the floors of 

 stellately arranged or longitudinal grooves, which give a characteristic appearance to 

 the sponge, and are chiefly placed on the inner surface of the branches, but also 

 occasionally on the outer surface and on the stem. Surface between the vent-bearing 

 grooves granular or minutely conulose. Texture compressible, resilient but tough, 

 with the stem a good deal harder than the branches. Colour (in spirit) rather light 

 grey. Total height of specimen 84 millims. 



The skeleton is rather loose and irregular, consisting (in the branches) of plumose 

 columns radiating outwards to the surface and with many spicules irregularly 

 scattered between ; the whole becoming quite confused towards the middle of the 

 branch, but without any special axial condensation. 



Spicules. (1.) Rather short and fairly stout styli (Plate XII., fig. 8) ; more or less 

 curved towards the base, which is broadly rounded off; gradually and sharply pointed 

 at the apex ; size about 0'295 millim. by O'OIG millim., but often more slender. 



(2.) Oxea ; almost symmetrically curved and gradually sharp pointed at each end; 

 of about the same dimensions as the styli ; abundant. 



This species, in the arrangement of the vents and in the skeletal characters, makes 

 a close approach to Pkakelha donnani and P. synimetrica, and demonstrates very 

 clearly the impossibility of distinguishing sharply between the genera PhokeUia and 

 Axinella. 



R.N. 53 (Gulf of Manaar). 



Axinella tenuidigitata, u. sp. Plate XIII., fig. 4. 



The single specimen is a small massive sponge of short, thick, irregularly cylindrical 

 form, attached by a broad base below and strongly convex on the upper surface, from 

 which a number of slender, elongated, finger-like processes are given off. Surface 

 uneven and irregularly hispid, especially on the digitiform processes ; in part minutely 

 and irregularly conulose and in part covered by a distinct, sub-glabrous, translucent 

 dermal membrane. The digitiform processes are solid and they may unite with one 

 another. Vents apparently small and scattered between the processes. Colour (in 

 spirit) pale wax-yellow ; texture hard and compact. Height of body about 

 20 millims., diameter about 15 millims. ; length of processes, of which there are about 

 half a dozen, about 11 millim:?., with a diameter of not much more than 1 millim. 



The skeleton in the body of the sponge consists of an irregular reticulation of long 

 styli, which, as they approach the surface, arrange themselves in loose, irregular, 

 plumose columns. The digitiform processes are composed each almost entirely of a 

 dense axis of similar spicules closely crowded together and placed longitudinally, 

 with a few spicules projecting outwards beyond the surface, so as to give rise to its 

 hispid character. 



