Sponges from South Australia. 315 



which there is no foreign material. Pores in the interstices 

 of the dermal reticulation. Vents numerous and small, scat- 

 tered over the surface in the intervals between the conuli. 

 Fibre sand-cored and simply keratose, almost colourless; the 

 mineral contents of the sand-cored fibre, which is scanty, 

 predominating over the keratose envelope ; structure compact ; 

 excretory canals numerous and small. Parenchyma more or less 

 charged with ova in different stages of development below the 

 more advanced segmental state. Size of specimen 7 in. 

 high, 2 x 2 in. horizontally in its greatest dimensions ; largest 

 process about 1 in. in its greatest diameter; compressed. 



Hob. Marine. 



Loc Port Phillip Heads, South Australia. Depth 19 fath. 



Obs. There is nothing strikingly specific in this specimen 

 beyond the uniformity of its conulated surface, in which the 

 conuli are comparatively small, mostly separate, well formed 

 and striated laterally in the dried fragment by folds of the 

 dermal membrane descending from their apices, the great 

 number of vents and the scantiness of the sand-cored fibre, in 

 which, as above stated, the mineral element far exceeds the 

 envelope of keratine. The great number of vents indicates a 

 great number of excretory canal-systems, and therefore corre- 

 spondingly small canals, thus leading to the compact character 

 of the parenchyma. 



Spongiophaga communis. 



Here is the place for me to say a few words on the " fila- 

 ment," which often replaces the whole of the sarcode or soft 

 parts in both the largest and smallest specimens of the cacti- 

 jorm Hirciniai with such fidelity that the pores and excretory 

 canal-systems are left intact as much as they would be in 

 their natural state ; indeed, such is the exactness with which 

 the sponge continues to be represented under this transfor- 

 mation, that even some of the best spongiologists have regarded 

 it as a distinct species. For this filament I long since pro- 

 posed the name of Spongiophaga communis, subsequently 

 describing and figuring it among " The Parasites of the 

 Spongida " (' Annals,' 1878, vol. ii. p. 168). 



It is almost impossible, in the smallest collection of Psam- 

 monematous sponges, not to find some specimens in which the 

 soft parts have been replaced by filaments of this enig- 

 matical organism ; so in Mr. Wilson's there are nine } of 

 which six are Hircinia?, one a specimen of my group Eu- 

 spongiosa and the other two in the fibreless Arenosa. That 

 this transformation should take place in different kinds of 

 Psammonemata, although chiefly in the cactiform Hircinice } is 



