402 DESCRIPTION OF [Rotat&ria. 



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 afterwards 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 

 movement of the propagula of the Vaucheriae, and as he 

 admitted the passage from vegetable life, characterized, 

 according to him, by immobility, to animal life, the prin- 

 cipal 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 

 Everghem, I 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 is was not a 

 propagulum, but a real animal, the Rotifer vulgaris, with 

 its cilia, wheels, tail, &c. 



" The first protuberances, or vesicles, which I saw, con- 

 taining 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 protuberances, whose development they may pos- 

 sibly stimulate, as the galls and oak-apples are organic 



