348 Messrs, S. 0. Kidley and A. Dendy on 



at intervals, size "65 by -0126 millim. : (2) equianchorates 

 of characteristic form, with three rather palmate teeth at each 

 end, and diamond-shaped "tubercle" [Carter) ; often the two 

 anterior teeth are united by their apices to one another ; 

 length '044 millim. The sponge also contains a good deal 

 of sand. 



Locality. Station 320, off Eio de la Plata, 600 fath. 



Genus SiDERODERMA *, n. g. 



Sponge with mammiform projections and a dense external 

 rind of closely packed, horizontally laid skeleton-spicules, and 

 a soft internal " choanosome " (Sollas). Skeleton-spicules: 

 smooth, bicapitate cylindricals. Flesh-spicules : equiancho- 

 rates, trichites, and (usually) bihamates. 



Sideroderma navicelligerum (Ridley) f- 



Hemispherical, sessile. Rind hard and dense, composed of 

 densely packed bicapitate cylindricals ; about 1 millim. thick. 

 Surface covered by numerous papilla?, some vent-bearing. 

 Pale yellow. Spicules : — (1) bicapitate cylindricals with a long 

 cylindrical shaft and an oval head at each end, length "28 to 

 •595 millim., diameter in middle of shaft "0063 to "0126 

 millim. ; (2) very fine long trichites, in bundles measuring 

 about "45 by "17 millim. ; (3) contort bihamates, large, mea- 

 suring -06 by '0047 millim., and small measuring "0189 by 

 •0015 millim. ; (4) tridentate equianchorates, length 'OIQ 

 millim.; (5) very minute equianchorates of peculiar form, 

 shaft much expanded laterally all along, so as to become 

 oval and flattened, and notched in front in the centre, with 

 one small oval tooth at each end, sharply recurved ; length 

 •01 millim. I 



Locality. Station 188, off New Guinea, 28 fath. 



Genus lOPHON (Gray). 



Skeleton-spicules : — (1) dermal, cylindrical, usually bicapi- 

 tate ; (2) main, acuate, generally more or less spined. 

 Flesh-spicules : — (1) palmate inequianchorates, the small end 



* aibripos, iron ; Sepjia, the skin, 



■\ " Crella navkeUigera, Ridley, Voyage of H.M.S. ' Oliallenger,' 

 Narr. of Cruise, vol. i. part 2, p. 571. 



4. We are indebted to the kindness of Dr. R. v. Lendenfeld for the 

 opportunity of examining' a second species of this remarkable genus, 

 which occurs in his large collection, whereby we have been able to give 

 a more satisfactory generic diagnosis than would otherwise have been 

 the case. 



