Mr. II. .1. (.'artcr <>u the Parasites of the Sponges. ,'531 



filament."*, wliicli have a evil at one end and a .•spiral twist 

 tlirou^liout, adniit.s that they are ditierent tVoni the .'<))oiii;t'- 

 ceW par excel leuce («'. e. the .sponge-animal), and alter alluding; 

 to Kolliker's doubt in 18()(), viz. whether it be a part of the 

 sponfje or a parasite, a^^ree.s in 1S70 (Atlantisch. Spong. Faim.) 

 with Kiillikt-r, that the two .strueture.s, viz. the sponge-fibre 

 and the tiltrilhe, are ditierent, finally ending with the ex])res- 

 sion that, after nuieh tronble, he ean state nothing further 

 re.speeting the natin-e of the latter. 



In his critique on the .synonymy and species of the Kerato- 

 spongia, in 18G4, Schmidt observes, respecting Auliskia, that 

 Dr. Bowerbank's illustration of his so-called "compound 

 fistulose keratose fibre'' in this genus {I. c. pi. 14. fig. 268, and 

 Annals, /. c. ])1. 13. figs. 1 c*t 2) proves that it is nothing more 

 than an " Alga,'' and therefore, being no genus at all, that the 

 name should be expungi'<l. 1 came to the same conclusion 

 before finding that Schmidt had done so ; but am not sure 

 whether the branched filament is part of the mycelium of a 

 ]\[ucor, or an Alga allied to Pythium enfophi/ftuii among the 

 Saprolegniea?. .Many genera of the Mucedines, especially 

 Botnjtis, infest the Sponges; but I have not yet, to my know- 

 ledge, seen one Saprolegniea3. Dr. Bowerbank's illustrations 

 of his so-called '' fil)rillated sponge-fibre " of the " Australian 

 sponges " (/. c. pi. xvi. figs. 280 & 279) are also of the same 

 kind. In short, no tortuous branched fibres of the sort are 

 proper to the SpongiadcT ; and hence all genera based upon 

 them should be sup])ressed. 



The " East-Indian Sponge," too {J. c. pi. xx. fig. 307), 

 which Dr. Bowerbank gives in illustration of the " inhalant 

 areas " in this species — Dr. J. E. Gray has correctly stated 

 (Proc. Zool. Soc. May 1867, p. 514) that the latter are nothing 

 more than polypes, " probably a parasite like the genus Bergia 

 of Michelotti." But I do not w^onder at Dr. Bowerbank's 

 mistake here, wdien, in the figure 374 following, he represents 

 the pol}q)es oi Hyalonema as the " oscula of a columnar cloacal 

 system "(!). 



Of such parasitic polypes there is one which is entirely iso- 

 lated, another which is concatenated by a stoloniferous pro- 

 longation of the {.olypidom (viz. that figured by Dr. Bower- 

 bank as " inhalant areas "), a third in groups, as in Schmidt's 

 Palythoa on the sponge Axinella, and a fourth in a con- 

 tinuous polypidom entirely surrounding the glass rope of 

 Hyalonema. 



It seems to me absolutely necessary that, if any one would 

 describe a sponge with accuracy, he should be generally ac- 

 quainted with all, or at all events with most of the knowii 



25* 



