116 T'liivirsitii of California Publications in Zoologtj [Vol. 16 



the parabasal as a slender strand terminating in a small eliroinatic 

 granule. This extension is possibly an axostyle and the terminal 

 granule is not to be regarded as the blepharoplast. 



The parabasal body, or so-called kinetonueleus, is found in these 

 early stomach phases at varying levels from the extreme posterior tip 

 (pi. 14, fig. 1) to a level half way from the tip to the posterior end of 

 the nucleus (fig. 8). It varies much in size, shape, and degree of 

 stainability or of extraction of the stain. It may be spheroidal (fig. 1), 

 ellipsoidal (fig. 5), trilobed (fig. 8), or even irregular (fig. 7) in 

 shape. It is intensely stained in some instances ( fig. 7 ) . shows a 

 central dark granule and a peripheral lighter zone (fig. 6), or may 

 have a light center and dark ends (fig. 1). These facts tend to sup- 

 port the view advanced by us (Kofoid, 1916) that the "kinetonueleus" 

 is in reality the parabasal body or kinetic reservoir, fluctuating in the 

 volume of its .substance with the changing internal conditions and 

 motor activities. 



The position of this parabasal body is not fundaiiit-ntally and 

 morphologically an axial one at the base of the flagellum, but rather 

 a lateral one, attached to the blepharoplast and pendant by the fan- 

 shaped parabasal rhizoplast. In certain views it appears to be axial 

 (pi. 14, figs. 8, 18). In others (figs. 5-7), even in the typical trypano- 

 somes of the early stomach phase, it appears to be laterally attached. 

 This spatial relation is most clearly demonstrable, however, in the 

 crithidial phases (pi. 14, figs. 14, 15). 



The cytoplasm in our material of the early stomach phase stains 

 rather deeply, leaving a clearer zone riuining lengthwise below the 

 marginal flagellum in the undulating membrane. The stainability of 

 both nucleus and cytoplasm and the variability of the parabasal are 

 indicative of a physiological state in the organism verging on degen- 

 eration, though not far advanced in any of the individuals. 



2. Late stonuich phase. — Minchin and Thomson (1915) find that 

 intracellular multiple fission ensues rather quickly, intracellular stages 

 appearing as early as eight hours after the flea had fed upon an 

 infected rat and continue for as much as five days, and possibly 

 longer. None of our material has been examined within two days 

 after possible opportunity to feed on the wood rat, so that the possi- 

 bility that some at least of the trypanosomes had already passed an 

 intracellular stage is at least open. We have not as yet seen, how- 

 ever, any intracellular stages. Nevertheless we interpret certain 

 stomach stages (pi. 14, figs. 9-12) found in a bug which was removed 



