392 COLLECTIONS FROM MELANESIA. 



granules, lying in a diffusely stained subtransparent matrix of the 

 same colour, but paler. A transparent membrane, consisting of an 

 almost colourless matrix, containing few purple granules, appears to 

 invest the fibre. 



Huh. Thursday Island, Torres Straits, 4—5 fms. ; bottom sand, or 

 sand and rock. 



Distribution. " Indian Ocean " (Pallas). 



Obs. In many particulars this species recalls Aphjsina purpurea of 

 Carter, but appears to differ fundamentally in the distinctness, large 

 size, and non-multiplicity of the fibres ; whereas in that species the 

 axes of the conuli and the skeleton generally consist of aggregated 

 masses of fine fibrils. If Hyatt's species is really like IaniheV-a 

 homei, with which he compares it, it cannot be this sponge, as it 

 would be of flattened growth ; but he appears to be uncertain on 

 the point. 



If one of the dermal cones, with the surrounding membranes, is 

 treated with a strong solution of caustic potash, a dark brownish- 

 yellow colouring-matter is dissolved out, thereby differing from 

 that of Ianthella, which is said to be violet under similar circum- 

 stances (Gray, Proc. Zool. Soc. 1869, p. 50) ; nothing of the tissues 

 is left but a branched fibre or two and some floeculent matter ; 

 therefore the only truly fibrous structures here are the terminal 

 twigs of the skeleton. 



The wall of the main skeleton-fibre of this species is much thicker 

 than in most Aplysince, and its axial substance is not granular. 



20. Ianthella flabelliformis. 



Spongia flabelliformis, Pallas, Elench. Zooph. p. .°>80. 

 Ianthella flabelliformis, Gray, P. Z. S. 18G9, p. 50. 



A specimen in spirit, somewhat imperfect, and not showing any 

 of those exfoliations of the lateral surfaces which specimens com- 

 monly exhibit. 



Bab. Port Darwin, 7-12 fms. ; bottom sand. 



Distribution. Indian Ocean (Pallas); " Australia" (Gray). 



CHALINID^E. 



In this family must now be included some forms with minute 

 flesh-spicules. Homoeodictya, Ehlers, is the earliest discovered case 

 of this combination ; and I am able to add another, in a new genus, 

 Toxochalina, which possesses fine tricurvates scattered in the sarcode. 

 I have relegated lihizochaliua to the Desmacidinida3 for reasons given 

 below (family Desrnacidinida?). I have also given reasons for a 

 belief that Platyclialina, Ehlers, is a Ceratose sponge (see Euspongia, 

 supra). 



The fact canuot bo ignored that the genus Toxochalina, charac- 

 terized below, runs counter to the plan of classification hitherto 



