176 The Mastigophora 



the unattached flagellates, as nectomonads. Attachment may involve loss 

 of the distal portion of the flagellum, although the axoneme persists 

 between the kinetoplast and the tip of the body (Fig. 4. 41, J). 



On the basis of life-cycles, six genera have been recognized (285): 

 Crithidia, Herpetomonas, Leishmania, Leptomonas, Phytomonas, and 

 Trypanosoma. Only leptomonad and leishmanial forms are found in 

 Leptomonas, Leishmania, and Pliytomonas. 



Fig. 4. 41. A, B. Leptomonas patellae Porter, leptomonad and leish- 

 manial forms; x3120 (after P.). C, D. Leishmania chamaelonis Wenyon, 

 leptomonad and leishmanial forms; from cloaca of Chamaeleon vulgaris; 

 x2750 (after Wenyon). E-G. Crithidia euryophthalmi McCulloch, from 

 Euryophthahnus coyivivus; leishmanial stage from hind-gut, crithidial stage 

 (with narrow undulating membrane) from crop, and crithidial haptomonad 

 from hind-gut; xl875 (after McC). H-K. Trypanosoma lewisi; form from 

 blood of the rat, small metacyclic trypanosome from hind-gut of flea, two 

 crithidial haptomonads from the hind-gut, and a stage in intracellular re- 

 production (stomach of flea); H-J, x2400; K, xl350 (after Wenyon). L. Tryp- 

 anosoma brucei, xl800 (after Wenyon). M-R. Herpetomonas muscarum, 

 leptomonad form, two crithidial stages, trypanosomal form, and two leish- 

 manial stages; xI600 approx. (after Wenyon). 



