274 CLASS: MASTIGOPHORA 



flagellate forms numerous chromatin bodies occurred. The organism was 

 never plentiful in the films. It was named Trypanopsis malignus by its dis- 

 coverer. The figures resemble very closely the forms which appear in films 

 as described above, and the writer feels that the possibility of the flagellate 

 having arisen from a slightly contaminated distilled water was not excluded. 



Another fallacy which may occur is the result of contamination of 

 exposed blood-films or smears by house-flies, which are very commonly 

 infected with Herpetomonas muscarmn. The flagellates are frequently 

 passed in large numbers in the fseces of flies, and such faeces deposited on a 

 film may be smeared over it by the fly itself or in some other way. When 

 stained, the presence of flagellates in the film will be liable to cause 

 confusion. 



When an animal which has died is opened for examination, smears 

 made from the liver, spleen, or other organs are very readily contaminated 

 with the intestinal contents if the intestine has been opened even very 

 slightly. Yeasts or even flagellates may thus contaminate the smears and 

 lead to a wrong diagnosis. In practically all these cases it will be found 

 that, in addition to the flagellates, the films contain a varied assemblage of 

 bacteria, the presence of which should always give rise to suspicion. It 

 is a common practice to open up animals which have been shot with the 

 object of making films from the heart-blood and organs. A slight wound- 

 ing of the intestine has often led to the passage of intestinal contents 

 into the peritoneal cavity, and consequent contamination of blood-films. 



DIVISION OF MASTIGOPHORA INTO SUB-CLASSES AND ORDERS. 



Certain Mastigophora resemble plants in that they are provided with 

 chromatophores containing chlorophyll, by means of which they lead a 

 holophytic existence. They may secrete capsules composed of cellulose, 

 while many of them possess red pigmented stigmata. These forms, 

 which are very closely allied to the unicellular algte, have been placed 

 by Doflein (1916) in the sub-class Phytomastigina, to distinguish 

 them from the Zoomastigina, which includes the flagellates which 

 have a holozoic method of nutrition, and are evidently animal in nature. 

 The latter ingest, solid food at all parts of the body surface like amoebae by 

 means of pseudopodia or through a special opening, the cytostome, or 

 they absorb by osmosis only preformed proteid matter in solution. 



The members of the sub-class Phytomastigina are mostly free-living 

 organisms which in many cases are closely related to the algae. Many of 

 them possess chlorophyll and have a holophytic mode of life. Reproduc- 

 tion is by binary fission, while syngamy, which is either isogamous or 

 anisogamous, commonly occurs. Certain Euglenoidida are parasitic in 



