466 COItEOTIONS FROM MELAITESIA. 



spirit-specimen in the present collection is in reality entirely in- 

 crusting, though apparently in part erect and cylindrical, owing to its 

 growing along the stem of a Tubularian Hydroid, which is planted 

 on the back of the crab on which the sponge-growth commenced. 

 In the thicker parts of the sponge the spicules form long tracts, 

 about 6 spicules in breadth, connected by interdigitation, or by 

 loose, irregularly crossing spicular tracts. The sarcode is snbtrans- 

 parent, somewhat granular, diffusely stained of a' reddish-brown 

 colour. The spicules in both the type and the present specimen 

 measure about ■25 millim. in length by '0063 miUim. in the 

 diameter of the shaft. 



Hah. Port Curtis, Queensland, 7 fms. 



Distribution. " Probably the seas of America " {Lamarck). 



HYMENIACIDON. 



Bowerbank, Man, Brit. Spong. i. p. 191. 



It appears to me that Bowerbank's genus should be retained for 

 those sponges with spiculo-flbrous skeleton without horny matter, 

 but in which primary lines are distinguishable, breaking up at the 

 surface and more or less within the sponge into tufts (thus forming 

 tracts which represent the secondary fibres of Eenieridse), and in 

 which there is but one form of spicule, a slender skeleton acuate 

 with or without indications of incipient spinulation. Such are the 

 characters derived from H. caruneula, Bowerbank, the species 

 which that author (Z. e.) has named as the type of his genus. It 

 differs from Suberites in the absence of distinct spinulation of the 

 skeleton-spicule. Schmidt refers this sponge to Amorphina (Spong. 

 Atl. Geb. p. 76), although he assigns in his diagnosis {op. cit. 

 p. 40) acerate spicules to that genus, which belongs to the family 

 Henieridae, whereas Hymeniacidon s. str. is decidedly a Suberitid, 

 closely allied to Suberites, 



95. Hymeniacidon canmciila, Bowerbank. 



A broad, horizontally extended specimen from a crab's back ; it 

 presents a few short mamiUse on its free surface. The form of the 

 spicules and arrangement of the skeleton are fully in accordance 

 with the type specimens of this British species. The spicules mea- 

 sure -23 to -29 by -0063 to -008 millim. ; those of the type specimen 

 from Tenby, -19 to -32 by -0063 to -008 millim. 



jffah. Port Jackson, 5-7 fms. 



Distribution. British seas {Bowerbank). 



96. Hymeniacidon agminata. 

 (PiATB XLI. fig. E; Plate XLIIL figs./,/'.) 



Aggregations of erect, flexuous, more or less compressed stems, 

 8 to 10 millim. in longest diameter, anastomosing; subdividing in a 



