LOWER AND HIGHER FORMS. 



As already stated, some kinds of animals are exceedingly 

 simple so simple, that they have the animal characteristics 

 only in the feeblest degree. The Amoaba (Fig. 1 arid fig. 

 2 6 ) for example, a microscopic form found in pools and 

 ponds, has neither mouth nor stomach, nor organs of any 

 kind. It is indeed an animal without definite form or 



FIG. 1. 



V; 



Amoeba radiosa. Magnified over 100 diameters. 



structure, and is, essentially, a mere particle of slime-like or 

 mucous matter, or sarcode, as such structureless animal 

 matter is called. One part is essentially the same as any 

 other. To no particular part or parts is assigned a spe- 

 cial function ; but the functions of sensation, voluntary 

 motion, and of nutrition, are apparently exercised by one 

 part as much as another. On coining to a particle upon 

 which it would feed, the Amo3ba envelops and digests it, 

 any part of the animal performing the functions of tentacles, 

 mouth, or stomach, as occasion requires.* 



A vast number of kinds of animals have no more or 

 higher animal characteristics than the Amoeba has. Some 



O 



of these low forms, highly magnified, are shown in the 

 accompanying wood-cut (Fig. 2). 



But going upward in the scale of animal life, we find 

 the structure more and more complex, according as the 

 animal is higher in rank, till in those animals which mav 



O ' 



properly be called the higher forms, we find an exceeding- 



* It must be stated here that Professor H. J. Clark ( "Mind in Nature," 

 p. 10) found the Amoeba invariably progressing with a certain part of the 

 body, forward ; and be called this part the head. 



