THE HJIMOFLAGELLATES. 211 



ing to Dutton and Todd the cytoplasm in T. mega and 

 (though to aless extent) in T. karyozeukton shows marked 

 differences in different regions of the body. In the third of 

 the body in front of the nucleus (fig. 58) it is very spongy, 

 and appears loose and alveolar in character ; behind the 

 nucleus it is arranged in alternating light and dense, deep- 

 staining bands ('' hyaloplasm" and " spongioplasm "), run- 

 ning more or less longitudinally. In Trypanophis there 

 are one or two rows of highly-refractive, yellowish inclusions 

 running the length of the body (figs. 40 and 41). The larger 

 ones lie in the row nearer the convex side, close to the undu- 

 lating membrane, and these may be oblong in shape, arranged 

 at right angles to the length of the body. These grains are 

 probably not comparable with those next described. Keysselitz 

 thinks they represent collections of fatty and oily substances. 



In many forms deep-staining grains or granules, of a 

 chromatoid nature, and of varying size are to be observed in 

 the cytoplasm.^ These are few and minute in T. danilewskyi 

 (fig. 60 a) and T. tinc^ (60 b), somewhat more numerous in 

 T. equinum (16 d), and T, theileri (fig. 60), and relatively 

 large and numerous in T. brucii, and certain individuals of 

 Trypanoplasma borreli (fig. 17 g). Inmost instances the 

 granules are, if not confined to, chiefly distributed in the 

 flagellate half of the body (in the case of Trypanoplasma, 

 the posterior half). In T. nelspruitense (17 e) and T. 

 granule sum (17 k) the grains are large and particularly 

 numei'ous, and, in the latter parasite, spread forwards almost 

 to the non-flagellate end. 



In certain Trypanosomes a vacuole is often, though by no 

 means constantly, to be observed, situated at a varying dis- 

 tance from the non-flagellate end. This vacuole is well 

 defined, usually of oval shape, and sometimes very prominent, 

 especially in certain Mammalian forms, e.g. T. brucii (fig. 

 44), T. gambiense (figs. 16 c, 48), and T. e van si (fig. 

 45). Prowazek (I.e.) also describes, for the first time, the 

 occurrence of one in T. lewisi. Laveran and Mesnil are 

 ^ For their probable origin and nature see below, p. 229. 



