396 Mr. Hoee’s Observations on the Spongilla fluviatilis, 
In the first place, as to the peculiar motion of sliding or creeping exhibited 
by pieces of the Spongilla in the water, I have no doubt that much the same 
may be seen on detaching portions of some plants belonging to the Ulve, 
Fuci, &c., when placed in that fluid, and that it arises from some other cause 
than, that of such contractile and expansive powers as are known to pertain to 
animal life. Indeed portions of some Fuci, especially of the leaves or fronds 
of Fucus vesiculosus, F. serratus, &c., I have been distinctly informed, on 
being torn from the original plant and put into water, show their edges roll- 
ing up and forming what might be esteemed by some as a sort of contraction, 
and in other respects varying and altering their newly-divided margins. And 
in corroboration of this statement, I will here add these appropriate words of 
Dr. Johnston: “I may remark on these experiments (of Dujardin), that loco- 
motion is no proof of animality. Several Algæ are locomotive *.” 
Now these changes in form of small parcels of the Lake Sponge are ac- 
counted for by M. Dutrochet, by a “mouvement de transport des globules 
élémentaires d'un lieu dans le lieu voisin; ces globules vésiculaires ne sont 
point immobiles dans leur adhérence mutuelle; ils se meuvent les uns sur les 
autres sans quitter leur adhérence par une sorte de glissement, et cela par 
l'effet d'une force inconnue qui appartient au tissu vivant. C'est une action 
vitale nouvelle qui joue certainement un des principaux róles dans le phé- 
noméne de l'accroissement en longueur des végétaux, accroissement qui est 
quelquefois d'une rapidité singulière | Xe 
In the second place, the filaments that M. Dujardin describes as being 
“ flagelliformes très longs d'une ténuité extréme," with which the pieces of 
Spongilla lacustris are externally furnished, evidently appear to me to be 
either the terminating capillary fibrest, which I have generally noticed grow- 
| ing beyond the surface of the membrane that envelopes the parenchymatous 
jelly in the River Sponge, or else some species of a Cryptogamic plant, such as 
a Conferva, or an Oscillatoria, &c., which has parasitically grown upon that 
substance; for I have constantly observed a Conferva-like plant with long, 
* Compare Johnston's Brit. Zooph., p. 325. 
t See Annales des Sciences Naturelles, tom. 
1 These will, I conclude, readily explain what M. de Lamarck means by “ subpiliferis” and « pili- 
t., tom, ii. p. 98, edit. 1816. 
