1916] Sirczij: Kiiictoinicleus of FlngcUntcs 217 



spring the two unequal flagella, is situated at the anterior end and 

 is connected with the nucleus by a slender rhizoplast (fig. 30). Thus 

 far it agrees in every essential detail with the typical Boclo. It will 

 be seen in the following discussion of the various forms found in 

 these amphibians that the propriety of separating them from Bodo 

 may well be doubted, as all stages in the development of an elaborate 

 parabasal structure from a simple blepharoplast, as in Bodo. will be 

 shown. 



Janicki (1915) also questions the propriety of separating Prowa- 

 zekia and Bodo, on the ground that the nuclear nature of the para- 

 basal body of Prowazckia is doubtful, and that this structure is sus- 

 ceptible of another interpretation. The chromidial body of Bodo, 

 "corps siderophile" of Alexeieff, he homologizes with the parabasal 

 body of the Triehonymphida, a conclusion which agrees with my own 

 reached before the appearance of his paper. The form which he 

 figures as Bodo lacertae is apparently identical with the species desig- 

 nated here as Prowazckia lacertae. 



The simplest form of the parabasal body is that shown in figures 

 24, 25, consisting of a number of granules surrounding the actual 

 blepharoplast, or it might be described merely as an enlarged blepharo- 

 plast. No distinction in these figures can be drawn between the 

 blepharoplast and the surrounding darkly staining material. A slight 

 modification of this is shown in figure 25, where the parabasal body is 

 becoming distinctly separated from the blepharoplast. A still further 

 separation, with a rounding up of the chromidial mass, produces the 

 type of parabasal body characteristic of Prowazckia cruzi (fig. 20). 

 The figures 26 to 31 illustrate the backward migration of the para- 

 basal body until it reaches a position close beside, or immediately be- 

 hind the nucleus, a condition comparable to that found in Critliidia, 

 but differing from it in that the blepharoplast does not take part in 

 this migration. It presents, however, some interesting modifications. 

 In figure 27 the parabasal body is still slightly in front of the 

 nucleus. It has become greatly enlarged, exceeding the nucleus in 

 size. The most interesting point here is its connection with the 

 blepharoplast. This granule is slightly elongated, and starting out 

 from the posterior portion of it, are a number of fibrils which spread 

 out in a fan-shaped figure as they reach the parabasal body to which 

 they are attached as a sort of a suspensory apparatus. At nearly equal 

 distances between the points of attachment are two granules, unequal 

 in size and spreading across the entire width of the fibrillar structure. 



