386 Mr. Hocc’s Observations on the Spongilla fluviatilis, 
causing all those temporary, and apparently spontaneous, movements both in 
the seeds or sporules*, and in the granules of vegetables. 
Wherefore it is manifest, that the very similar movements of the sporules 
belonging to many water-plants, and of the gemmules of Zoophytes, are not 
effected by the same means; yet, nevertheless, the design and object of such 
movements are without doubt the same, namely, a proper dispersion of the 
different species throughout the waters of the deep,” and thus evincing a no 
less wonderful than a beneficent mark of an Allwise Power, in providing for 
the continuation and safe increase of even the most minute objects of created 
being. 
Again, let me proceed to enumerate to you certain other facts which have 
come under my observation tending to prove the vegetable nature of the 
Spongilla fluviatilis. 
The first, that I must mention, is the resemblance of the membrane which 
clothes the soft portion or jelly, and entirely lines the pores and canals of that 
Sponge, with that of the leaves of plants; this membrane or cuticle is ex- 
tremely thin, delicate, transparent, and colourless, and seemed under the mi- 
croscope which I used as if most finely reticulated. 1 examined with care the 
membranes of the leaves of many common plants, amongst which were the 
daisy, cabbage, stock, primrose, lettuce, geranium, spinach, and thick-leaved 
saxifrage, and to me their general similarity of appearance both in texture 
and in transparency with the membrane of the Spongilla was obvious. "Though 
whether the delicate membrane of the latter be cellular, as Amici states is the 
case with that of leaves, or merely porous, or not, I have been as yet unable 
to discover by reason of my not having at hand a sufficiently high magnifying 
power. 
M: Dutrochet has described in the valuable memoir before quoted, the 
* It is not unlikely that a number more of the seeds both of freshwa: 
marine plants (Thalassiophyta) will hereafter be discovered to possess, 
motive property. 
t I suspect, however, that if this membrane of the Spongilla were examined under a more power- 
ful microscope, it will be found to 
possess a minuter resemblance with th h 
leaves or fronds of the Fuci. e external membrane of the 
water plants (Hydrophyta) and of 
for a short time, the like loco- 
