291 
to our Knowledge of the Spongida. 
infusorium Euplotes , whose legs, being as numerous and active 
as those of a crab, must have their moving powers all regu¬ 
lated by similar contrivances ? yet we might as well look for 
these as the structure in glass! To assume that such fibrillas 
do not exist because they are not appreciable by our senses is 
to assume that the finite can comprehend the infinite. 
Of course I can say nothing of the “ ampullaceous sacs,” 
which are made up of the spongozoa (“Ultimate Structure 
of Spongilla f 1857, loc. cit.), the “ Wimperkorbe ” and 
“ Geisselkammern ” of the Germans, as these delicate parts have 
long since passed out of sight with the freshness of the sponge; 
but it is desirable to state here that Dr. F. E. Schulze, in a 
preeminent paper on the recent species of Sj>ongelia,^^x do apud 
Schmidt (Spong. Adriat. Meeres,1862, p. 28 , = Dysidea, John¬ 
ston), has observed that the ultimate branches of the pore- 
tubulation open through numerous small holes or fissures into 
the ampullaceous sac {Geisselkammer), and that the latter, on 
the other hand, opens by one large one into the excretory 
canal (Zeitschrift f. wiss. Zool. 1878, Bd. xxxii. p. 134). This 
is somewhat different from what I have stated of Spongilla in 
1857 {op. et tom. cit. p. 27, &c.), and may be more to the 
purpose; at the same time, as it is so easy to grow the young 
Spongilla from the seed-like body in a watch-glass, and,feeding 
it with carmine, to observe what takes place with a high 
power (|-inch objective), immersed, it would be desirable, 
since Dr. Schulze’s description, although taken in part from 
living specimens, was not made under the same circumstances, 
to repeat the observations on Spongilla in the way that I have 
described {loc. cit.), always remembering that the soft parts of a 
sponge, being in their active state, ever changing in form 
like the Amoeba , can apparently extemporize an aperture or 
close it, temporarily or permanently, wherever required. Dr. 
Schulze’s paper and drawings are alike admirable, and the 
lithographed photographs a model for all time in the matter 
of sponge-representation. 
Lastly, I would direct attention to the typical form given of 
the flesh-spicule of Axos spinipoculum , as a variety of that 
group which I propose to describe and illustrate hereafter under 
the name of “ Sceptrella .” 
Echinonemata, Cart. 
Family 1. Ectyonida, Cart. 
Genus Tkikentrion, Elders. 
In 1864, Dr. Bowerbank (Mon. Brit. Spongiadas, vol. i. 
