TRICHOMONAD FL.\GELLATES. 305 



Bensen's (1909, PI. 9) figures of T. mgiiialis indicate an axostyle 

 formed by a continuation of the rhizoplast through the nucleus and 

 karyosome to the posterior end of the body. This interpretation 

 seems improbable in the light of our own results and of the later 

 figures of this species given by Brumpt (1913). It is probable that 

 the structure here interpreted as rhizoplast-axostyle is in reality the 

 chromatic basal rod lying beneath the nucleus, and that Bensen has 

 found neither rhizoplast nor axostyle. In so far as structure and 

 position go this latter interpretation is equally open and on compara- 

 tive grounds practically certain. 



It is also possible that the structure interpreted by Brumpt (1913) as 

 the axostyle in T. vaginalis and T. intestinalis of man is in reality the 

 chromatic basal rod or parabasal. Its stainability, position, and 

 structure indicate this interpretation. The axostyle in T. vaginalis 

 as figured by Brumpt lies on the opposite side of the nucleus from the 

 undulating membrane, and bends about it. It is a slender deeply 

 staining thread, with one liae of chromidia on either side of it in the 

 distal part of its course and is itself at times resolved in part into 

 detached chromidia in a single or a double line. In T. intestinalis 

 the same author also figures a chromatic axostyle which lies between 

 the nucleus and the undulating membrane. In position and structure 

 it is very much like the chromatic basal rod of T. augusta, a structure 

 which would seem to be absent here if we should accept Brumpt's 

 interpretation and call this the axostyle, unless one of the "filaments 

 de soutien" which he mentions but does not figure, represents this 

 basal rod. However, comparison of existing figures of these species 

 with those of Brumpt certainly reveals the probability that neither 

 one of these chromatic structures is the axostyle and that they are 

 both really the chromatic basal rods. The position of the true hyaline 

 axostyle of T. vaginalis may be represented by the projecting point 

 in his figure 119, 2, and of T. intestinalis in a similar point in his 

 figure 120, 1 and 3. The displacement of the undulating membrane 



initial stages of the formation of the new parabasal in this species, nor have we 

 found the stout condition which Janicki figures as his parabasal. We find no 

 sufficient evidence in his later paper to modify our earUer conclusion that the 

 chromatic basal rod of Trichomonas is the homologue of the parabasal of the 

 Trichonymphida as described by Janicki (1911) and that the organ which he 

 interprets in Trichomonas as the parabasal is only an unusual or abnormal con- 

 dition of the outgrowing new parabasal at mitosis. This interpretation of ours 

 is supported not only by our own observations but also by the comparative 

 absence of the parabasal of Trichomonas of Janicki in nearly all of the litera- 

 ture of this group. 



