150 University of California Publications in Zoology [Vol. 19 



a sacklike structure from the region of the blepharoplast. Unlike the 

 suspensory apparatus of C. leptocoridis, C. euryophthalmi does not 

 show a fan-shaped mass of contractile cytoplasmic fibrils covering this 

 axial portion, which is of blepharoplastic origin (figs. A, 1, 2; figs. B, 

 1-5). The outline of this cytoplasmic envelope in C. euryophthalmi is 

 definite, slightly opaque, and continuous with the cytoplasmic sheath 

 of the flagellum. 



The parabasal body of the trypanosomes (figs. A, 3, 4, 5) is simi- 

 larly a bar-shaped structure, which stains deeply, located to one 

 side of the nuclear rhizoplast and blepharoplast. In T. leivisi (fig. 

 A, 3) the parabasal body is relatively small while the blepharoplast is 

 correspondingly large. As previously noted, no parabasal rhizoplast 

 has been figured by Minchin and Thomson in T. Leivisi. Here and 

 there suggestions of a connection might be pointed out in their figures. 

 While it is possible that T. lewisi is exceptional in this respect, yet, . 

 since the structure is found in other flagellates of this group, we may 

 infer that a critical study of the preparations with a binocular micro- 

 scope will reveal the presence of such a connection in the crithidial 

 stages of this flagellate. 



Trypanosoma leivisi (fig. A, 3) is likewise the only flagellate here 

 figured in the crithidial stages without a nuclear rhizoplast. Here 

 again T. leivisi is either exceptional or the structure has perhaps been 

 overlooked, since it is usually discerned with difficulty. Chagas (1909) 

 has figured a nuclear rhizoplast in Schizotrypanum cruzi and we have 

 found it also in T. triatomae. Therefore we may expect that it will 

 be found in T. lewisi. 



The parabasal body in Trypanosoma triatomae (fig. A) is a rela- 

 tively large structure, its width approximately equal to one-half of its 

 length. It is located a short distance anterior to the nucleus, and is sus- 

 pended from the blepharoplast by a fan-shaped parabasal rhizoplast 

 like that of Crithidia leptocoridis, i.e., a suspensory apparatus with a 

 fibrous appearance. In the crithidial stage of T. triatomae a nuclear 

 rhizoplast was observed connecting the blepharoplast with the centriole 

 of the karyosome, but such a connection was not found in the trypani- 

 form individuals. If a nuclear rhizoplast be present in the trypaniform 

 stage, in which we did not find it, it is possible that we may have been 

 prevented from observing it because of the density of the cytoplasm 

 in this stage and a tendency in this delicate thread in the trypano- 

 somes to stain lightly. In the crithidial stages of this trypanosome, on 

 the other hand, the cytoplasm is more or less vacuolated in appear- 

 ance thus making the nuclear rhizoplast more evident. When a try- 



