ii8 Dzicllcrs of the Sea and Shore 



food. But even this statement, although essentially 

 accurate, is subject to qualification. Numerous excep- 

 tions abound. As a matter of fact there are some 

 animals which are nourished like plants, and there exist 

 certain plants which subsist only on food material 

 already formed. 



Now all this is not to say that what are commonly 

 recognized as plants are animals in masquerade, or 

 the reverse; it is, however, a way of stating that t!.e 

 gulf between them is far more apparent than it is real. 

 Between the higher individuals of both kingdoms the 

 relationship, of course, is not so generally obvious. 

 But when we turn to the lowest of all living forms, 

 the one-celled organisms, an undisputable kinship mani- 

 fests itself. Indeed, there occur among these some 

 w^hich have identities that are neither distinctly plant- 

 like nor are they truly animallike ; rather they are both ; 

 that is to say, they are half vegetable and half animal. 

 The little green Euglena of fresh-water ponds and 

 streams is a classical example of organisms which, so 

 to speak, are on the borderland. This pretty, but 

 paradoxical, creature — if I may so call an organism 

 which is also an undoubted plant — has given rise to 

 considerable friendly controversy among naturalists as 

 to its proper place in nature. Botanists as well as 

 zoologists claim it as their own. 



But our lowest plants merit an attentive considera- 

 tion quite aside from any of the foregoing reasons, for 

 they are presumed to be the present-day representatives 

 of the first living things to appear on this planet. The 

 history of the earth is a thrilling record of vast and 

 impressive changes, not only in the appearance and the 



