too, that is what it is. Moreover, flatworm is its 

 common, besides being its appropriate, name. 



A glance at its exterior alone would have dis- 

 cerned all that was necessary to know that a great 

 gulf lay between the flatworm and the highly or- 

 ganized Nereis; but with more careful examina- 

 tion came a fuller realization of the vastness of 

 that chasm. Inwardly as well as outwardly there 

 was every evidence of a remoteness from one an- 

 other exceeding by far that which exists between 

 the monotremes and man. 



To begin with, it had no respiratory organs, its 

 breathing being carried on through its skin and 

 perhaps the countless cilia which covered its body. 

 Consequently it had no blood-vascular system, as 

 by this simple process of obtaining its oxygen, 

 none was needed. But little else would be required 

 to indicate its low organization than to mention 

 the fact that this flatworm can be cut into several 

 pieces and each piece will regenerate a smaller, 

 but perfect replica of the original. A modification 

 of this power of regeneration sometimes gives rise 

 to seemingly rare and peculiar forms not infre- 

 quently found free in Nature : if by accident they 

 become merely mutilated, bizarre and freak shapes 



[173] 



