384 Mr. Hocc’s Observations on the Spongilla fluviatilis, 
than either to the locomotive gemmules of Zoophytes, or to the Volvoces* 
themselves, we may justly conclude that the sporules of the Sponges are of a 
vegetable nature. 
Furthermore, I consider that those hairlike, vibratory, and minute append- 
ages called cilia, as instruments of locomotion, acting somewhat after the 
manner of little oars or fins, are peculiar to animals and to animal substances, 
and that they never can exist upon any vegetable production whatever. 
Grant, Dalyell, Farre, Johnston, and others, describe the gemmules of Zoo- 
phytes as being furnished with these cilia, and that by them alone they are 
impelled through the water. The body of the Volvox globator is likewise 
covered with similar organs according to Professor Ehrenberg, who has be- 
sides discovered that the cilia of the Infusoria have extremely small muscles 
attached to their roots, by which the vibratory motions are performed. "Those 
naturalists, then, who reason solely from analogy, would, from the similar 
movements of the sporules of the Ectosperma and Sponges, at once decide that 
all those sporules move by the same means by which the Infusorians and the 
gemmules of the Zoophytes do, and consequently, that they have such cilia. 
But here analogy is of no assistance: for these organs of locomotion have 
never yet been discovered on any vegetable body, although sought for with the 
aid of very powerful magnifiers. M. Donné very recently, in endeavouring to 
ascertain the cause of the circulation in the Chara, pressed out from a tube of 
the Chara hispida a great number of granules ; amongst these were seen some 
which had a rotatory movement, more or less rapid, independent of the 
movement of general circulation: some turned round on themselves without 
changing place: others were carried along by the current, but still preserving 
their spontaneous rotatory movement. He supposed that they possessed cilia 
as organs of their motions, but records, “I examined if there existed vibra- 
^ : 3 ACH 
des — examinations of some of the Infusoria, (among others) of Monas lens, Kolpoda 
cucullus, Brachionus ovalis, &c. have shown to me, that in addition to the characteristic distinctions 
pointed out in the text, these animalcula plainly differ from the locomotive sporules of the Spongilla 
by their great restlessness, and by their being almost cons à : 
i : tantly e d in searching for, or huntin 
after, their food or prey.—J. H., Feb. 12, 1839. y engage meis or, or hunting 
T Of soie, I med scarcely observe, those fine hairs or fringes, which are named cilia by botanists, 
and occurring on different vegetable substances, are perfectly distinct. 
