Volvocina.] THE INFUSORIA. 123 



means of which each animalcule is fixed to the base of 

 its own special envelope. Each one is furnished with a 

 filiform proboscis, which gives the appearance as if the 

 whole sphere were covered with hairs. When the creatures 

 divide, the mantle, or lacerna, only enlarges, without 

 becoming separated itself. The visual organ is a red 

 speck in the fore part of the body, and the tail is filiform, 

 resembling that of the Vorticella and Bodo. 



The internal structure of these compound animalcules 

 can be verified only with instruments of superior quality, 

 and require considerable skill in the management of 

 them. This latter qualification is so indispensable, that 

 notwithstanding many persons in this country possess 

 better microscopes than those employed by Ehrenberg, 

 the curious organization of these little creatures has 

 hitherto eluded their observation. 



82. UROGLENA volvox. The rolling Uroglena. Body 

 composed of yellow corpuscles of an oblong form. Tail 

 extensible from three to six times the length of the body, 

 and even more. Cluster mulberry-shaped. There is little 

 doubt but that single animalcules of this genus, seen in 

 company with the clusters, have often been taken for 

 creatures of a different family. Ehrenberg states that he 

 has observed individuals with two or three eyes, which he 

 conceives to have been a symptom of approaching self- 

 division. Fig. 54 gives a magnified representation of a 

 globular cluster of these animalcules, and^. 53 a single 

 one, in which the red eye is distinctly visible. Found in 

 turf water. Diameter of cluster l-90th. 



Genus XXII. EUDORINA. The globe Animalcule with 

 an eye. The characteristics of this genus are its absence 

 of tail, but possession of the eye, which may be distinctly 



