68 



GENERAL BIOLOGY 



pal groups of algae by reference to any good text book of 

 botany. The identifications of unusual forms that may be 

 found will be facilitated by the use of the plates in such 

 works as Wolle's Fresh Water Algae, Wood's Fresh Water 



Algae of North America 

 West's British Fresh Water 

 Algae, and keys in such 

 works as Lampert's Das 

 Leben der Binnengewasser 

 and Stokes' Analytical Key 

 to the Genera and Species 

 of the Fresh Water Algae 

 and Desmidiae of the Uni- 

 ted States. 



The record of the results 

 of this study may be pre- 

 served in a few simple out- 

 line drawings, showing for 

 the larger forms, a diagram 

 of the manner of growth, 



FIG. 50. Micrasterias (after Carpenter.) 



A to F, successive stages in cell formation. an( ^ a drawing showing 



the cell form and the distribution of chlorophyl. Nucleus, 

 protoplasm, cytoplasm, and other internal parts may be 

 taken for granted, and need not be sought out nor repre- 

 sented in this record. 



SOME TYPICAL PROTOZOANS. 



The simplest animals are the Protozoans. In a much 

 greater proportion than in the algae, the cells exist singly. 

 Like the unicellular algae they consist of few parts, and such 

 of those parts as they have in common are found in every 

 cell nucleus, cytoplasm, inclusions, etc. 



Amoeba (fig. 51) is one of the simplest of animals. We 

 call it an animal because it moves about freely and feeds on 

 other organisms ; but at first sight it seems wholly lacking 



