176 ANIMALS AND PLANTS. [LECT. 



gether unlike Heteromita. The small end, however, 

 is not produced into one long cilium, but the general 

 surface of the body is covered with small actively 

 vibrating ciliary organs, which are only longest at the 

 small end. At the point which answers to that from 

 which the two cilia arise in Heteromita, there is a 

 conical depression, the mouth ; and, in young speci- 

 mens, a tapering filament, which reminds one of the 

 posterior cilium of Heteromita) projects from this 

 region. 



The body consists of a soft granular protoplasmic 

 substance, the middle of which is occupied by a large 

 oval mass called the " nucleus ;" while, at its hinder 

 end, is "a " contractile vacuole," conspicuous by its 

 regular rhythmic appearances and disappearances. 

 Obviously, although the Colpoda is not a monad, it 

 differs from one only in subordinate details. More- 

 over, under certain conditions, it becomes quiescent, 

 incloses itself in a delicate case or cyst, and then divides 

 into two, four, or more portions, which are eventually 

 set free and swim about as active Colpodce. 



But this creature is an unmistakable animal, and 

 full-sized Colpodce may be fed as easily as one feeds 

 chickens. It is only needful to diffuse very finely 

 ground carmine through the water in which they live, 

 and, in a very short time, the bodies of the Colpodce 

 are stuffed with the deeply-coloured granules of the 

 pigment. 



And if this were not sufficient evidence of the 

 animality of Colpoda, there comes the fact that it is 

 even more similar to another well-known animalcule, 



