﻿Trypanosome found in Pontobdella. 107 



Figs. 17, 18, 19. Smaller broad forms, to show variation in shape and 

 appearance. 



Figs. 20-23. Intermediate forms between Fig. 16 and Fig. 25. 



Fig 2-lr. Trypanosome to show variation in shape. 



Fig. 25. Long slender trypanosome ; possibly male form. 



Figs. 26 and 27. Slender trypanosomes from the proboscis of the leech. 



Figs. 28-42&. Development of locomotor apparatus. 

 Fig. 28. Kounded-off form, with segmenting kinetonucleus. Xote the 

 division is a longitudinal one (Stage 1). 



Fig. 29. The distal segment of the kinetonucleus shows signs of a trans- 

 verse division (Stage 2;, 



Fig. 30. The distal segment of the kinetonucleus has grown out to form 

 the two preflagellar bodies. Xote their attachment to the 

 kinetonucleus, and also the appearance of the kinetonucleus, 

 which is preparing for division (Stage 3). 



Fig. 31. Much about the same stage as 30, but the kinetonucleus is 

 elongated preparatory to division. The cross-bar at the 

 base of the preflagellar bodies is very definite in this figure. 



Fig. 32. Division of the kinetonucleus. This has occasioned the separating 

 of the proximal ends of the preflagellar bodies The cross-bar 

 is represented by the two little red bodies towards the left of 

 the two daughter kinetouuclei. 



Figs. 33 and 34 illustrate the out-growth of the flagella. They both show 

 the red cross-bar. 



Fig. 35. The kinetonucleus is divided, and the preflagellar bodies are 

 separated from each other. 



Figs. 36 and 37 show division of the protoplasm. 



Fig. 38 shows later stage. The preflagellar body, both in this and in 

 Fig. 89, suggest that the flagellum has grown out from the 

 axial part of the preflagellar body. 



Figs. 39-425 show the development of the Crithidial or Herpetomonas- 

 like stage nto the trypanosome. Xote the quite indiff'erent 

 distribution of the protoplasmic inclusions. 



Figs. 43-49. Division of the trophonucleus. 

 Fig. 43. Early stage of division. The plane of division of the tropho- 

 nucleus is here parallel to the longiradinal axis of the body. 

 In the centre of the nucleus the two sets of chromatic 

 particles, derived apparently from the karyosome, are to be 



