6 HANDBOOK OF PROTOZOOLOGY 



tribution of apparently one and the same species. For example, 

 Sandon found Amoeba proteiis in samples of soil collected from 

 Greenland, Tristan da Cunha, Gough Island, England, Mauri- 

 tas, Africa, Argentina, and India. This amoeba is known to oc- 

 cur in various parts of Europe, North America, Japan, and Aus- 

 tralia. Most of the Testacea live in moist soil in abundance. 

 Sandon in his survey referred to above found Trinema enchelys 

 (p. 242) in the soils of Spitzbergen, Greenland, England, Japan, 

 Australia, St. Helena, Barbadoes, Mauritus, Africa, and Argen- 

 tina. 



Fig. 1 Encystment of Euglypha acanthophora. X320 (After Kiihn). 



Of the Protozoa living in close association with other 

 animals, symbionts, commensals and parasites will here be 

 considered. Certain Protozoa live within the bodies of other 

 animals in a kind of association that is apparently of mutual 

 benefit. They are called symbionts. The relation between ter- 

 mites and some Hypermastigida which inhabit the formers' 

 intestine is a typical example of symbiosis. According to 

 Cleveland, these flagellates digest the cellulose substances which 

 are eaten by termites and transform them into glycogen- 

 ous substances which are used as food by the insects. If de- 

 prived of these flagellates by being subjected to oxygen under 

 pressure, the insects die, and if the wood diet of the termites 

 is stopped, the flagellates die. In this connection, it may be 

 mentioned that no one of the enormous number of species of the 

 Hypermastigida has ever been found in encysted condition. It 

 is presumed that the young termites become the hosts to the 

 flagellates when ' they feed upon freshly voided fecal matter 

 of the older ones already containing the flagellates. 



