46 PROTOZOA 



References on Protozoa 



BuTSCHLi, O. 1889. Protozoa, in Bronn's Tierreich. 



Calkins, G. N. 1901. The Protozoa. Lemcke and Buechner, New 



York. 

 Calkins, G. N. 1909. Protozoology. Lea and Febiger. 

 Calkins, G. N. 1926. The Biology of the Protozoa. Lea and Febiger. 

 Clarke, J. J. Protozoa and Disease. Pt. i, London, 1903; Pt. 2, 



London, 1908. 

 Conn, H. W. 1905. Protozoa of Fresh Water of Connecticut. Bulletin 



Geological and Natural History Survey of Connecticut. 

 Craig, C. F. 1926. A Manual of the Parasitic Protozoa of Man. J. B. 



Lippincott Co., Philadelphia, Pa. 

 DoFLEiN. 1927. Lehrbuch der Protozoenkunde. Jena. 

 Leidy, J. 1879. Fresh-water Rhizopods of North America. Govern- 

 ment Printing Office. 

 Minchin, E. a. 191 2. Introduction to the Study of the Protozoa with 



Special Reference to the Parasitic Forms. E. Arnold, London. 

 Sandon, H. 1927. The Composition and Distribution of the Protozoan 



Fauna of the Soil. Oliver & Boyd, Edinburgh. 

 Stitt, E. R. 191 8. Practical Bacteriology, Blood Work and Animal 



Parasitology, 5th edition. Philadelphia and London. 

 Waksman, S. a. 1927. Principles of Soil Microbiology. Bailliere, 



Tindall and Cox. 

 Ward, H. B., and Whipple, G. C. 191 8. Fresh-water Biology. John 



Wiley and Sons. 

 Wenyon, C. M. 1926. Protozoology, 2 vols. Wm. Wood & Co., N. Y. 



Metazoa. (Gr. meta^ beyond; zoon^ animal.) — As we have al- 

 ready shown (page 13), the Metazoa include all the Phyla above the 

 Protozoa. The Metazoa begin as single cells, the fertilized eggs or 

 ova, but early in their embryonic life they form two or three cell 

 layers^ from which develop the organs and structures of the adult 

 animal. The germ cells are functional in reproduction, while the 

 body (somatic) cells carry on all other functions. To what extent 

 the germ cells (germplasm) may be affected by the somatic cells 

 (somatoplasm) and by environmental influences, is the basis of 

 considerable controversy. (See page 514, Inheritance of Acquired 

 Characters.) The somatic cells form tissues^ the discussion of 

 which is deferred to a later chapter. (Page 426.) 



