44 GENERAL ORGANIZATION OF THE PROTOZOA 



the anterior flagellum has disappeared apparently, leaving only the 

 undulating membrane and the distal flagellum as motile organs. 

 Finally, in spirocheta, especially in Spirocheta balbianii, both free 

 flagella have disappeared, leaving only the undulating membrane, 

 while in some species of spirocheta even this remnant of the motile 

 apparatus has disappeared, leaving the organism with no visible 

 means of locomotion. As such forms of spirocheta move with great 

 freedom, it is not incredible that the remnant of the contractile ele- 

 ment is still retained within the membrane of the cell. 



In a number of forms the flagella are numerous and distributed 

 uniformly around the body. Many of these tvpes are of doubtful 



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systematic position and are placed by some students of the group in 

 the class ciliata while others regard them as flagellates. The nature 

 of the flagellum in such cases justifies the mastigophora affinities, for 

 they are long and undulating and have the characteristic flagellum 

 movement. Such is the case in multicilia, actinobolus, myriophrys, 

 etc., and in parasitic forms like trichonympha, pyrsonympha, etc. 

 Other features of the cell body, however, such as the nuclei, tricho- 

 cysts, etc., indicate relationship with the infusoria, and to classify 

 such questionable forms as one or the other type shows the artificial 

 character of even the best system of classification. The difficulty is 



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one that is constantly met with bv svstematists. and in this case it 



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serves a useful purpose by indicating the very close connection between 

 the ciliated and the flagellated protozoa. 



The single flagellum is usually inserted deep within the substance of 

 the body, sometimes, as in euglena, at the base of an opening at the end 

 of the body; this opening, known as the flagellum fissure, is the means 

 of exit of the waste matters of the cell, thrown out by the contraction 

 of the contractile vacuole. The flagellum originates deep within the 

 substances of the protoplasm and usually in the vicinity of the nuclear 

 membrane. The energy constantly freed by protoplasmic oxidation 

 is here concentrated, apparently, in the constantly moving material 

 of the flagella. The contractile material, formed within the nucleus 

 or at its periphery, as in the case of Camptonema mutans, is of similar 

 nature to the material of the heliozoon axial filaments as shown in the 

 case of dimorpha, and is associated in some way with the material 

 of the mitotic figure or division centre, as shown by its origin 

 from the blepharoplast in herpetonionas, crithidia, trypanosoma, 

 and trypanoplasma. The flagellum, therefore, is an element of the 

 cell formed from the active or kinetic substances that are intimately 

 associated with the nucleus. It is not merely a periplastic or mem- 

 brane prolongation which may arise at any point on the cell periphery, 

 but is much more deeply involved in the protoplasmic make-up. The 

 real flagellum is permanent, thrown off and reproduced again, only at 

 times of cell division. This point has importance in view of the ques- 



