STRUCTURAL DIFFERENTIA TIONS 



139 



locomotion in the dense media in which the parasites live and in 

 which the flagella would be ineffective. They are closely connected 

 with the blepharoplasts in all species of (Hardia (Fig. 140, p. 293), 

 and are regarded as independent, self-perpetuating organoids which 

 may be the first to divide in the processes of reproduction (Giardia) 

 or the last to divide (Trichomonas). In all cases the axostyle 

 divides longitudinally throughout its entire length, beginning with 

 divisions of the anterior end in which the blepharoplast may .be 

 embedded (Fig. 72). 



Fig. 



■Trichomonas augusta Alex. Two successive stages in division of the axo- 

 style. (After Kofoid and Swezy.) 



In regard to the two opposing points of view as to the-function 

 of axostyles the weight of probability rests with the interpretation 

 of Kofoid and Swezy (1915). The necessity of a supporting struc- 

 ture, or a form-rectifying organ, in these parasitic types is difficult 

 to conceive. On the other hand their intimate relation to the 

 blepharoplasts and their activity in reproduction indicate a common 

 function with the kinetic elements. The observations of Kofoid 

 and Swezy on the energetic movements of the axostyle while the 

 organism works its way through the mucous afford a more plausible 

 interpretation of the function of this organoid than the a priori 

 views of those who see in such movements only the efforts of an 

 elastic supporting structure to restore the form of a pla.stic cell. 



