ORGANISATION 



313 



Fig. 150.— Various Forms assumed by Flagellates of the Genera Lepto- 



monas (1-16), Crithidia (17-26), and Trypanosoma (27-50). (Original.) 

 The lines represent the surface of epithelium to which flagellates become attached. 

 1-4 and 5-7. Evolution of round form (cyst) into leptomonas form 8. 

 9-11. Attached forms in which the flagella are lost. 

 12. Overgrown cercoplasma form. 

 13-16. Retrogression of leptomonas form into round form (cyst). 

 17-20. Evolution of round form (cyst) into crithidia form. 

 21-23. Attached forms in which flagella are lost. 

 24-26. Retnigrc'ssiou of crithidia furm into round form (cyst). 

 27-29. Evolution nf round form (cyst) into trypanosome form. 

 30-39. VarinustyiK'.s of trypanosome form. _ . 



40-42. Attached forms in which Hagella are lost, but undulatmg membrane is still 



present. 

 43-45. Attached forms in which flagella are lost and no undulating membrane present 



(RhjTichoidomonas forms). 

 46-47 and 48-50. Retrogression of trypanosome form to round form (cyst). 



