310 Mr. H. J. Carter on the Animality of Freshwater Sponges. 
dijfiuens (Muller) *; that which chiefly accompanies No. 4 is of 
the figure given by Dujardin, to which I have already had occa- 
sion to allude ; while the vibrating bodies themselves, when com- 
bined, take on the appearance of minute Proteans, and every 
particle of the fixed transparent granule- gelatinous matter, which 
serves as a nidus for the whole, appears to be endowed with the 
power of continually extending, retracting, and altering its 
shape. 
I have further observed, that the granulo-gelatinous trans- 
parent matter has in some places arranged itself into the forms 
of full-sized spicula, disposed in linear continuation, over-reach- 
ing each other side by side, just as they are seen in the fibrous 
structure of the old sponge; their surfaces however are not yet 
silicified ; nor should I expect this to take place, as my experi- 
ments have been conducted with distilled water, had not Dr. 
Grant mentioned that siliceous spicula were formed in the gem- 
mules of Spongilla which he nourished with rain-water. 
Thus does every step towards the ultimate structure of the 
Freshwater Sponge, every form that is taken by the living mat- 
ter of which it is composed, appear still more nearly to approxi- 
mate it to the nature of the genera of Ehrenberg^s Pseudopodia. 
In a subsequent communication received from the author, he 
observes, that he has confounded two species under the head No. 2, 
and that the bright green coloured species there mentioned is 
distinguished from all the rest by having a crust of double- 
pointed smooth spicula round its seed-like bodies. He supposes 
this to be Spongia lacustris (Linn.), Spongilla friahilis (Lam.). 
Further, he observes respecting the animality of the Freshwater 
Sponges, that the animals of which they are but a congeries are 
identical with the infusorium Proteus \ 1st, because they are 
composed of a semi-transparent gelatinous matter ; 2nd, because 
this gelatinous matter is endowed with the power of altering its 
shape and of locomotion ; 3rd, because in it are seen transpa- 
rent cells [contracting vesicles) of various diameters from 1 -9000th 
part of an inch to a mere point (which he formerly supposed to 
be sphinctral orifices), dilating and contracting themselves as in 
other animalcules; and 4th, because this gelatinous matter is 
provided with greenish yellow granules moving with, and espe- 
cially characteristic of both the Proteus and the animal of the 
sponge. 
He regards the Proteus as being more active in changing its 
shape, &c. than the animals of the sponge when first torn from 
each other, from the habits of the former having been vagrant 
* Dlainville, Manuel d'Actinologie (Atlas, pi. 11. fig. 12). 
