THE GENUS TRYPANOSOMA 



249 



criticism that no sexual phases have as yet been found in the blood of 

 vertebrates is not wholly unanswerable, since we do not yet know 



'I'ryiiaiii.soma raia-. (After Rubertson.) Forms observed in tlie (iigestive tract of the leedi, 

 I'outobdella inuricata. .1. iiiaturc specimen from blood of skate; B to F, stages in the 

 development of the fiaKi'lluin ficin the kinetonucleus, ami cliange in position of the latter in 

 relation to the nurlous. 



much about the conjugation processes in any species, while Hintze's 

 view is conceivable, viz., that the organisms migrate from the blood 

 l)ack into (he intestine, wliei'e lliey conjugate, while in blood-suckiiig 



