INFUSORIA. 



33 



living atoms, includes under the term Infusoria, animalcules essentially 

 remote both in their general characters and intimate organization. 



(64.) The Infusoria, as characterized by M. Dujardin, are creatures 

 which, when examined under the microscope, appear to be composed of 

 a homogeneous, glutinous, diaphanous substance, and are either naked 



Fig. 15. 



3 mi? 



Euplotes Charon (Ehr.). 1. Animalcule seen from below, exhibiting the locomotive apparatus 

 composed of uncini, styli, and setae : v. the anal aperture. 2. Dorsal aspect of the same, covered 

 with a delicate shell. 3. A similar view showing the ciliary currents, the position of the mouth o', 

 the nucleus t, and the contractile vesicle . 4. Side view representing the animalcule creeping 

 upon the surface of a fragment. 5. Two animalcules conjoined by their mouths; in one, the 

 ventral, in the other the dorsal aspect is uppermost. 6. A specimen exhibiting the process of 

 reproduction by transverse fissure. 7. Destruction of the animalcule by diffluence of the soft 

 parts. 



or partially enveloped in a more or less resisting integument. Their 

 usual shape is rounded or ovoid. Some (and these are the forms 

 most commonly met with, which at once arrest the eye of the micro- 

 grapher) are provided with vibratile cilia, which, either used occasion- 

 ally or continually in motion, serve the purpose of innumerable oars 

 for the movements of the animalcule, or in some cases merely act as 

 agents in supplying provisions to the little creature's mouth; others 

 instead of vibratile cilia are furnished with only one or two or some- 

 times several extremely slender filaments, which they agitate with an 

 undulatory movement, and are thus enabled to advance through the 

 fluid wherein they swim ; whilst others, provided with neither cilia nor 

 flagelliform filaments, move about by simple contractions and extensions 

 of the general substance of their bodies. 



(65.) The forms last mentioned, as the reader will at once perceive, 

 naturally arrange themselves among the RHIZOPODA, described in the 



D 



