1895 THE MICROSCOPE. 185 



crassa, which are superb Infusoria with long sticks, small 

 horns and thick, slender and well visible cilia, we will 

 find after some time some Trichoda lynceus, which are 

 quite small and have a form which recalls this of the Clop- 

 ortae. Never would we believe that such a beautiful 

 Infusoria could be the larva of such an insignificant 

 animal, which differs a little from the ordinary type of 

 Infusoria. 



If we think that all their transformations are not yet 

 known, we Avill not be surprised at the continual re- 

 newal of what we have described as distinct species. 

 When the water evaporates, the Infusoria die or are en- 

 cysted. There again their forms change very much. If 

 we add water again to the preparation, they continue to 

 live under odd forms, which have caused them to be des- 

 cribed as if they. Avere durable. It is thus that we have 

 mistaken certain cyclidium for Proteus tenax and so many 

 other deliquescent Infusoria and Rhizopods for Amoeba, 

 of very distinct species. A little quantity of water is, 

 indeed, sufficient to make an Infusoria or only a part of 

 its protoplasm live under the amoeboidal form. Certain 

 Rhizopods, with soft body, not protected by a skeleton 

 sustain thus complete modifications, which causes us to 

 believe in the production of new Infusoria. 



The Paramoecium aurelia can present, following a pre- 

 liminary coupling, a series of olives disposed like a collar? 

 which are simply spermatic capsules. It presents then a 

 peculiar aspect which has probably been the cause of 

 having it mistaken for another animal, with characteris- 

 tic nucleus. 



But they are still two beings of the same species, since 

 they are two different forms of the same individual. At 

 last, the wind which raises the germs of Infusoria, the 

 rain which beats the roof and takes away its Systolides, 

 the carpets shaken and which spread their dust, are 

 three causes which add new Infusoria to the cultures ex- 



