168 Mr. H. J. Carter on Parasites of the Spongida. 



an antipathy to the officinal sponge, in the midst of which it 

 may be seen to polymorphose the whole of the Hircima (when 

 the two have thus grown together), without sending a suigle 

 filament into the officinal sponge. 



After these statements it need hardly be added that the 

 filament is a parasite affecting many 

 kinds of sponges, and that therefore it 

 cannot form a sj^ecific character of any. 

 It will now be described, then, as such, 

 in the mass or tissue and in the ehmetit 

 respectively, under the name proposed 

 for it in 1871, viz. : — 



Spongiophaga communis^ Cart. 

 (See figure.) 



Tissue, when fresh, soft, flexible, gela- 

 tinous ; when dry, papyraceous, tough, 

 and when torn, in this state, tomentose. 

 Composed of fibrillai replacing partly or 

 entirely the sarcode of various kinds of 

 sponges, chiefly the Hircinida. Fibril 

 about one third of an inch long, com- 

 posed of a fusiform filament terminated 

 at each end by a bulbous inflation which 

 is similar; filament l|-6000th inch 

 broad in the centre, diminishing gra- 

 dually on both sides to half this dia- 

 meter at the extremities ; bulbous infla- 

 tion more or less ovoid with the narrow 

 end towards the filament, averaging 2 

 by l-i^-6000th inch in its greatest dia- 

 meters ; filament consisting of a trans- 

 parent sheath filled with a gelatinous 

 colourless substance in which no struc- 

 ture is visible until solution of iodine in 

 hydriodate of potass is applied, when it 

 becomes of an amber colour, assumes a 

 spiral form, and the whole filament, if 

 doubled upon itseJf, becomes rapidly in- 

 tertwisted like the strands of a rope, 

 returning to its natural state both out- 

 wardly and inwardly when the solution 

 of iodine is washed out with water, so 

 as to reassume its original appearance 

 in every way. Internal contents 



Sponyiophaya comtmmis 

 (artificially arranged). 



Scale about l-24th to 

 l-1800th inch. 



