a new Genus and S2)ecies of Monaxonid Sponges. 153 



Description of Species. 



Proteleia Sollasi. 



Sponge sessile, apparently coating (it has been torn off 

 from its attachment), consisting of a flattened cake-like expan- 

 sion with slightly convex upper surface, from which arise 

 abruptly numerous short, thick, cylindrical, mammiform 

 projections of various sizes. The single specimen in the 

 collection is about 2^ inches long by 1^ broad and not quite 

 half an inch thick ; the mammiform processes vary somewhat 

 in size, being when full-grown about ^ inch long by ^ inch in 

 diameter at the base; these processes are almost solid and 

 very stiff and firm, contrasting strongly with those of such 

 forms as Polymastia rohusta and P. mamillaris in this 

 respect ; at present they are all closed at the summit, and 

 it is doubtful whether any opening exists in the living 

 sponge, though what appear to be traces of such can be 

 found. Colour in spirit yellowish grey. Texture tough and 

 leathery, internally coarsely fibi'ous ; the cortex is very firmly 

 adherent to the underlying tissues. Surface between and on 

 the mammiform processes even, seen in sections to be minutely 

 hispid ; hispidity more strongly marked over the body, where 

 also there is a considerable amount of foreign matter collected, 

 than on the mammiform projections, which are almost gla- 

 brous in appearance. Vents (? minute, at summits of papillse). 

 Pores scattered (? singly) over the surface of the body and of 

 the mammiform projections. 



Skeleton : (a) Of the main Body. — (1) A thin, very dense, 

 and compact external layer (PI. V. fig. 1, ^), about '15 millim. 

 thick, composed of vertically-placed, tightly-packed, small, 

 straight, and slender spinulate spicules, with their apices 

 directed outwards and projecting for a short distance beyond 

 the surface of the sponge. (2) Immediately below the above 

 and inseparable from it a similar but very much thicker layer 

 of larger, stout, spinulate spicules, arranged as in the first 

 layer, and with their apices imbedded in it (PI. V. fig. 1, c) ; 

 thickness about '35 millim. These two layers together may 

 be regarded as the cortex. Besides the spinulate spicules 

 already mentioned there are, in the cortex, spicules of another 

 and very remarkable kind — the grapnel-spicules, to be de- 

 scribed later. These have the base and a portion of the shaft 

 imbedded in the cortex, while the remainder of the spicule 

 projects freely for a considerable distance beyond the surface 

 of the sponge, and bears at its extremity the grapnel. Imme- 

 diately below the cortex, as above defined, comes a layer, 

 about as thick as the second cortical layer, of still larger, 



