366 Mr. Hocc's Observations on the Spongilla fluviatilis. 
stantly seen specimens of this Spongilla of various sizes and gradations, and 
to all appearance as if they had originated or been produced from these sin- 
gular seedlike bodies. Moreover, last March, having procured some of these 
fresh bodies, I placed them in a glass vessel, nearly filled with spring water, 
and changed the water every day; six of them soon affixed themselves to the 
bottom of the glass*, and in about three weeks every one of them was covered 
with a whitish and wooll-like substance, which I took for the rudiments or 
commencement of the Spongef. After that time I was obliged to leave 
home, and consequently to give up all further investigations upon that in- 
teresting subject. 
I ought also to inform you, that I find from experiment these seedlike 
bodies, when dried and long kept out of water, exhibit no such appearances, 
and seem, when replaced in water, as if they had lost all their vitality and 
power of reproduction; neither have I perceived that they possess, even in a 
fresh state, any cilia nor any locomotive propertyf whatever, wherein they 
essentially differ from the similar germs, or ovules, or sporules, of certain spe- 
cies of the Sea Sponges, as described by Dr. Grant. 
Pallas in a note to his description of Spongia fluviatilis (p. 385. * Elenchus 
* This glass vessel, with these same specimens, 
1838. Upon examining the small white patches 
ments of the Spongilla, 
fibres or spicula. 
was exhibited to the Society on December 18th, 
with a lens, they were found to be the true rudi- 
having the cells or pores very distinct, and formed by the little anastomosing 
T A short time after this letter was read, my attention was called by my friend Professor Bell, to 
Mr. Gray * paper (with which I was previously unacquainted) in the Zool. Journ. vol. i., where at 
p- 50 I noticed that he mentions Squeezing the granules from some specimens of freshwater Sponge, 
and adds, There were a few partly decayed leaves at the bottom of the basin, on which the green 
granules fell. Being called away, I left them there for a day or two, when on my next examination 
I found they had formed a more velvety mass, 
through which visible fibres were shooting, which gra- 
dually enlarged, thus growing entirely after the manner of vegetables.” This is a pleasing confirma- 
tion of my own experiment, 
t nor has M. Dutrochet notíced the power of locomotion in the similar bodies which belong to the 
Spongilla lacustris. His remark is as follows : 
: " Enfin M. Grant a fait cette observation neuve et 
—— que les corps oviformes, ou les œufs de l'Éponge, lorsqu'ils sont détachés et devenus libres, 
sont inp de mouvemens spontanés comme des animaux, Je n'ai point fait cette observation sur les | 
corps oviformes de la Spongille, que je regarde comme des sortes de tubercules.” Vide Annales des 
Sci. Nat. tom. xv. p. 217. 
§ Vide p. 382. vol. xiii. of the Edinbu 
: rgh Philosophical Journal for 1825; p. 154 of the Edinb. 
New Phil. Journ. for 1826; and p. 129 of the same Journal for 1827. : 
