SPONGES. 221 



which stain deeply with picro-carmine, are about - 008 millim. in diameter and 

 somewhat variable in shape, sometimes nearly spherical and sometimes more or less 

 pointed at the end. 



Ridley's Dysidea fusca, which that author (16) supposed might be identical with 

 Carter's Hircinia fusca, appears to be quite a different sponge. 



U.N. 48, 99 (pearl banks, Gulf of Manaar) ; 271 (small specimen with fewer 

 filaments. " Deep water off Galle and onwards up West Coast of Ceylon "). 



Hircinia tuberosa, n. sp. Plate XVI., fig. 2. 



The sponge consists of a very irregular, somewhat tuber-like body, from which 

 irregular, linger-like processes are given off in various directions, the whole much 

 mixed up and partially coated with calcareous debris. In the largest specimen the 

 central portion of the sponge measures about 60 millims. in diameter, and the two 

 larger processes each about 44 millims. in length by 18 millims. in diameter. The 

 surface is very uneven, but sub-glabrous (not reticulate) between the foreign adhesions, 

 and only slightly conulose, the conuli being low, irregular, and widely separated from 

 one another. Internally the sponge is cavernous, being permeated by wide, cylindrical, 

 meandering vestibules, which are covered in at the surface of the sponge by a thin, 

 parchment-like dermal membrane, pierced here and there by rounded apertures. 

 These apertures are evidently vents. They vary from about 0'5 millim. to 4 millims. 

 in diameter, and are frequently arranged in groups. They are found sometimes on 

 the central portion of the sponge, but more frequently on the more or less fistular, 

 finger-like processes. Texture extremely coarse and gritty throughout, but tough. 

 Colour (in spirit) pale yellowish -grey throughout. There is a distinct but thin sand- 

 cortex in the parchment-like dermal membrane. 



The skeleton (Plate XVI., fig. 2) is an extremely irregular network of more or less 

 trellis-like horny fibre, partly enclosing and partly connecting together the very 

 numerous sand-grains and other foreign bodies with which the sponge is filled. 

 Main fibres are recognisable, but not very well defined, and the whole is so irregular 

 that it is useless to give measurements. 



The flagellate chambers are about 0"03 millim. in diameter and approximately 

 spherical, and the ground-substance between them is finely granular. 



Filaments are present in enormous numbers and usually collected together in more 

 or less dense bundles. They measure about 0'006 millim. in maximum diameter 

 between the heads, and their heads are approximately spherical and about - 008 millim. 

 in diameter. 



R.N. 86, 88, 88a (all from deep water off Galle and onwards up West Coast). 



Hircinia schulzei, n. sp. Plate XVI., fig. 3. 



Sponge slender, cylindrical, irregularly branched, and attached at many points to 

 fragments of calcareous debris, amongst which it appears to creep. A few rather 



