SFOXGIIDA. 443 



diameter about -07 millim. ; one or two axial series of spicules ; 

 both sets of tibres echinated .sparsely with the echinating spicule. 

 Dermal skeleton formed by undulating, very pale yellow horny 

 fibres containing two or three series of spicules, about '053 millim. 

 broad, and of loose tracts of spicules. Sarcode pale amber-yellow, 

 transparent. 



Spicules:— (1) Skeleton cylindrical, smooth, straight, tapering 

 slightly from middle towards well-rounded ends ; size about -2 by 

 •Oi)42 millim. (2) Echinating acerate, smooth, straight, tapering 

 decidedly from middle towards the base, which is thus thinner than 

 the middle of the shaft, hut is well rounded, and tapering from 

 middle to sharp point at apex ; size about -1:5 by ■(>< >95. (3) Tri- 

 curvate acerate, smooth, curves slight, ends finely pointed; size 

 about -042 by -0021 ; in sarcode. 



Hub. Port Molle, Queensland, 12fms. ; bottom rock and coral. 



In general appearance this sponge resembles Clathria frondifera, 

 but has the intervals between the trabecule of the clathrous struc- 

 ture more or less filled with membranous expansions. The spicula- 

 tion is not quite so simple as that of the British species, hut has. in 

 addition to their echinating acerate and tricurvate, a cylindrical 

 skeleton form. I know of no other near allies. A small but well- 

 preserved dry specimen represents this species. 



74. Clathria aculeata. 

 ( Plate XL. fig. I ; Plate XLII. fig. k.) 



Erect, with single, slender stem, dividing into branches at some 

 distance from base ; branches given off in various planes and at 

 acute angles, occasionally connected by bars of sponge-substance ; 

 secondary branches occur, formed in the same manner as the pri- 

 mary branches. Stem cylindrical, 4-5 millim. in diameter in pre- 

 sent specimens : surface even, with the exception of a few prominent 

 but blunt aculeations shortly below the commencement of the 

 branches ; branches well covered by loner, more or less pointed 

 aculeations, 2 to 5 millim. high. Texture of stem, both in spirit 

 and in the dry state, woody, incompressible ; that of the branches 

 elastic, but more or less incompressible until near the apices, which 

 | are firm but compressible. Colour, in spirit, dark amber-brown ; in 

 dry state pale brown, the branches having a whitish incrusted 

 appearance. Surface of branches, in spirit, minutely uneven, that 

 of stem glabrous. 



Main skeleton composed of very strong amber-yellow horny fibre, 

 )rtuous and anastomosing, not showing distinct separation into 

 arimary and secondary fibres, but forming oval meshes ; diameter of 

 fibre at base of branches varying from *05 to -2 millim., the short 

 diameter of the meshes formed by it at the same spot from -18 to 

 •8 millim. ; fibre cored by a tract of slender spinulate spicules, 3 

 or 4 spicules broad, and echinated everywhere abundantly by the 

 spined acerate spicule. Dermal skeleton similar to main skeleton, 



