Prof. Morren on Infusoria in Plants. 345 
of a capsule or vesicle. These vesicles are at first of a 
uniform bright green colour, and without increase of size, 
which exceeds several times that of the branches, they always 
become of a blackish-green colour, darker towards the base, 
and then one or two globules of a reddish-brown may be 
clearly distinguished there, often surrounded by smaller gra- 
nules, evidently destitute of motion, whilst the great ones 
move spontaneously and slowly here and there in the interior 
of the capsule, by unequal contractions and dilatations, whence 
arise remarkable changes of form. I saw these globules, at 
the end of eight or ten days after their appearance, still in- 
closed in the capsule, moving more and more slowly, recei- 
ving no very decided increase, whilst the base of the capsule 
became more transparent; at last I observed that, instead of 
their expulsion, which I was watching for, the extremity of 
the capsule, at the end of some days, took an angular form, 
and subsequently gave birth to two expansions in the form of 
horns ; it remained in this state and became more and more 
pale, whilst the animalcule became darker and died, and after- 
wards it ended by perishing at the same time as the other 
parts of the conferva*.” 
Subsequent researches have not succeeded in informing us 
what this animal might be of which Unger spoke. As this 
author drew so much attention to the spontaneous move- 
ments of the propagula of the Vaucheriz, and as he admitted 
the passage from vegetable life, characterized, according to 
him, by immobility, to animal life, the principal criterion of 
which was motion, his animalcule was confounded with the 
propagula, and no one, so far as I know, has returned to this 
very interesting subject. 
When, therefore, I found the Vaucheria clavata at Everg- 
hem, | was as much surprised as pleased to see the mobile 
body noticed by Unger better than he did. With the aid 
of a higher magnifying power, I found it easy to ascertain the 
true nature of the animal, for it was not a propagulum, but 
a real animal, the Rotifer vulgaris, with its cilia imitating 
the wheel, its tail, &c. : 
The first protuberances or vesicles which I saw containing 
this animal, inclosed but one of them ; afterwards they laid 
eggs and multiplied ; but it seems that then they descend the 
tubes of the Vaucheria and lodge themselves in new protu- 
berances, whose development they may possibly stimulate, as 
the galls and oak-apples are organic transformations attribu- 
table to the influence of parasitic beings. 
* Annales des Sciences Naturelles, ancienne série, t. xiii. 1828, p. 438. 
