.SKELETAL OR SUPPORTIXG STRUCTURES 



43 



and passes through the centre of the body to protrude with a sharp 

 point at the posterior end. It is a structure which has little affinity for 

 stains, and its function and origin are not properly understood. Some- 

 times the flagellates are seen attached to debris by the pointed extremity 

 of the axostyle, but this is possibly only accidental. It is, perhaps, best 

 to regard the organ as skeletal in nature. Not infrequently, as explained 

 above, some of the axonemes which arise from the blepharoplasts at the 



(: 



Fig. 27. — Trichomonas vaginalis, showing tendency of Axostyle to Split into 

 A Series of Fibrils ( x ca. 2,000). (After Reuling, 1921.) 



anterior end of the body, instead of becoming free flagella at the anterior 

 end, pass backwards through the cytoplasm to become free flagella at 

 other parts of the body surface. This condition is well seen in Hexamita 

 and Giardia (Figs. 288 and 291). It is customary to speak of the intra- 

 cytoplasmic portions of the axoneme in these flagellates as axostyles, 

 but this is clearly a misapplication of the term, for there is no evidence 

 that the axostyle of Trichomonas has any real homology with an axoneme, 

 though Kofoid and Swezy (19L5) have suggested that it represents an 



