SPONGES. 185 



(2.) Oxea (Plate XII.. fig. 2, d, e) ; slender, sub-fusiform, slightly curved or 

 angulated once or twice, sharply pointed at each end; size very variable, averaging, 

 say, about 0"2 millim. by 0*0055 millhn. These spicules occur chiefly at the surface 

 of the sponge, but are also found in the interior. 



This species differs widely from Spongosorites topsenti, not only in external form 

 but also in the (? invariably) stylote character of the larger spicules. 



R.N. 236 (deep water off Galle and onwards up West Coast of Ceylon). 



Spongosorites (?) lapidiformis, n. sp. Plate XII., fig. 3. 



The three specimens by which this species is represented in the collection are quite 

 irregular in shape ; massive, and everywhere evenly rounded off, like water-worn 

 pebbles, with no recognisable points of attachment or differentiation of surfaces. The 

 surface is granular and very shortly hispid ; harsh to the touch ; occasionally veined 

 by underlying ramifying canals. Vents few, small, sometimes hardly recognisable. 

 Texture hard and compact, without separable dermal membrane. Colour (in spirit) 

 pale wax-yellow. The largest specimen measures about 29 millims. in maximum 

 diameter. 



The skeleton is a very dense, irregular reticulation of megascleres, partly collected 

 together in ill-defined bands. This reticulation extends right up to the surface of 

 the sponge, and there is no special dermal skeleton, and apparently no spongin. 



Spicules. (1.) Very stout, fusiform oxea (Plate XII., fig. 3, a, b); slightly curved 

 and gradually and sharply pointed at each end ; measuring, say, about - 87 millim. 

 by - 0495 millim. ; pretty frequently becoming stylote (Plate XII., fig. 3, c) by 

 rounding off of one end, and rarely even strongylote. These oxea are connected by 

 intermediate forms (Plate XII., fig. 3, d) with 



(2.) Slender oxea (Plate XII., fig. 3, e) ; slightly curved, gradually sharp-pointed at 

 each end; measuring, say, about - 54 millim. by 0"012 millim. ; irregularly inter- 

 mingled with the large oxea, and perhaps only young forms thereof. 



This species is of very doubtful systematic position. Had it not been for the 

 presence of so many stylote spicules, I should probably have referred it to Hali- 

 chondvia. It differs from typical species of Spongosorites in the absence of a special 

 dermal layer of small oxea. 



R.N. 143, 144, 145 (all from deep water oft' Galle and onwards up West Coast). 



Hymeniacidon, Bowerbajntk (emend.). 



Axinellidse of massive habit. Skeleton reticulate, composed of spicular fibre usually 

 containing a good deal of spongin ; with no special dermal skeleton. Megascleres 

 styli or sub-tylostyli ; no microscleres. 



I have pointed out on a previous occasion (10) that Lexdenfeld's genus Stylotella 

 (with which Topsent's Stylinvs is admittedly synonymous) is not distinguishable 



2 B 



