TRICHOMONAD FLAGELLATES. 301 



remain intact after all of the cytoplasm macerates and disappears, as 

 it sometimes does. Smears sometinies reveal such remnants consist- 

 ing of the entire extra-nuclear motor apparatus (Fig. D, 4) still intact 

 except for the tip of the axostyle, and attached to the nucleus by a 

 slender fibrous rhizoplast (Fig. B, rh.) which passes posteriorly from 

 the blepharoplast along the side of the axostyle. We have not found 

 this rhizoplast in unmacerated individuals, where it does not stain 

 deeply, but may be hidden in the dense mass about the nucleus in the 

 stained preparations. 



The center, however, both structurally and developmentally, of 

 the extranuclear motor apparatus is the blepharoplast which is a 

 spheroidal deeply staining granule at the anterior end of the axostyle. 

 From it the three anterior flagella pass anteriorly out of the cytoplasm. 

 Into the outer rim of the undulating membrane goes the chromatic 

 margin and into its base the chromatic basal rod, both curving poste- 

 riorly on the dorsal side of the body and at their junction at the end 

 of the undulating membrane the posterior flagellum emerges as the 

 continuation of the chromatic margin. 



The anterior flagella {nnt. fl., Fig. B), three in number, are of equal 

 length and are as long or longer than the body. These flagella are 

 habitually directed anteriorly and strike together in a lashing back- 

 ward stroke which gives to the body a jerky or intermittent method 

 of locomotion when on the substrate. When at rest and often in 

 fixed material their outer two-thirds are reflexed. 



The fourth flagellum forms the outer or chromatic margin of the 

 undulating membrane. It runs posteriorly on the dorsal side curving 

 spirally on to the left side in a steeper or flatter spiral (PI. 1, Fig. 5) 

 according to the elongation or shortening of the body. It is longer 

 than the base of the membrane in whose margin it lies and is thrown 

 into a series of 6-9 subequal undulations which pass \\'ithout reversal 

 ceaselessly in the posterior direction. 



At the end of the membrane, which is a short distance above the 

 point of emergence of the axostyle, the imprisoned flagellum emerges 

 from the cytoplasm as the posterior free flagellum {yost. fl., Fig. B) 

 whose length may equal or exceed that of the body. W'ithin the 

 undulating membrane this flagellum is stained an intense black, but 

 outside of it the tone is the same as that of the anterior flagella. This 

 may be due to greater bleaching of the stain in the more exposed part 

 of the flagellum or to a chemical difference. There is no detectable 

 difl'erence in the diameters of the two parts. 



At the point of emergence it is attached to the posterior tip of the 



