18 General Morphology o£ the Protozoa 



J, K) is fairly typical of the Trypanosomidae, although the mastigont 

 of Leptomonas ctenocephali (151) is less simple. In addition to the kine- 

 toplast, a periflagellar ring in L. ctenocephali gives rise to a long para- 

 basal filament (Fig. I. 10, I). A simple elongated parabasal body is found 

 in certain uninucleate Trichomonadidae (Fig. 1. 10, A) and in each 

 complete mastigont of such multinucleate genera as Stephanonympha, 

 Calonympha, and Snyderella (Fig. I. 10, C-E). In certain flagellates a long 

 parabasal body is coiled around the axostyle (Fig. 1. 10, F), while the 

 apparatus of Macrotrichomoyias ramosa (126) is branched (Fig. 1. 10, G) 

 and that of Pseudodevescovina uniflagellata is compound (Fig. 1.10, B). 

 A complex apparatus, often including many separate elements, occurs 

 also in various Hypermastigida (47). 



The special term, hinetoplast (127), has been applied to the parabasal 

 body of trypanosomes and related flagellates. This usage seems justified. 

 Kinetoplasts are Feulgen-positive (104, 152, 188, 192) and are demon- 

 strable by methods of fixation and staining which are unsatisfactory for 

 the trichomonad parabasal body. Finthermore, the kinetoplast divides 

 in fission whereas this is rarely the case in other types of parabasal 

 apparatus. 



Multiple karyomastigonts and mastigonts 



The kinetic elements of many multinucleate flagellates have in- 

 creased in number along with their nuclei. Each flagellar unit (mastigont) 

 is associated with a nucleus in Coronympha and Stephanonympha (Fig. 

 1. 10, D). Such flagellates thus contain a number of karyomastigonts, each 

 composed of a nucleus and associated blepharoplasts, flagella, parabasal 

 body, and axostyle. This appears to be the primitive condition in such 

 flagellates. Two sets of flagella are associated with each of the four 

 nuclei in Polykrikos sclnvartzi (25); the flagellar apparatus has doubled 

 independently of the nucleus without otherwise disrupting the basic 

 karyomastigont (Fig. 4. 20, G). Caloyiympha represents an intermediate 

 condition showing both karyomastigonts and mastigonts, the latter being 

 far more numerous. A degree of specialization rare in flagellates — inde- 

 pendence of nucleus and mastigont — is represented by Snyderella tabogae 

 (Fig. 1. 8, C), in which the several dozen nuclei are all dissociated from 

 the hundreds of mastigonts. 



CILIA AND THEIR DERIVATIVES 



Cilia are structurally similar to flagella but are shorter and more 

 restricted in movement and are generally present in greater numbers. 

 Prorodon teres, for example, is equipped with about 11,600 cilia (231). A 

 cilium, like the flagellum, apparently consists of a sheath and an axoneme 

 ending in a basal granule. A "sensory" component has been described as 



