184 ANIMALS AND PLANTS. 



four, or more portions, winch are eventually set free and 

 swim about as active Colpodw. 



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 ani- 

 mality of Colpoda, there comes the fact that it is even 

 more similar to another well-known animalcule, Para- 

 mceciu?n, than it is to a monad. But Paramcecium is 

 so huge a creature compared with those hitherto dis- 

 cussed it reaches -^ of an inch or more in length 

 that there is no difficulty in making out its organisa- 

 tion in detail ; and in proving that it is not only an ani- 

 mal, but that it is an animal which possesses a somewhat 

 complicated organisation. For example, the surface layer 

 of its body is different in structure from the deeper 

 parts. There are two contractile vacuoles, from each 

 of which radiates a system of vessel-like canals; and 

 not only is there a conical depression continuous with 

 a tube, which serve as mouth and gullet, but the food in- 

 gested takes a definite course, and refuse is rejected from 

 a definite region. Nothing is easier than to feed these 

 animals, and to watch the particles of indigo or carmine 

 accumulate at the lower end of the gullet. From this 

 they gradually project, surrounded by a ball of water, 

 which at length passes with a jerk, oddly simulating 



