II. FLAGELLATA: AUTOFLAGELLATA 



183 



asexually. While most of the individuals of a colony are concerned with nutri- 

 tion and motion, others grow larger, and by rapid division, form new colonies. 

 There is yet uncertainty about the fertilization of the parasitic Auto flagellates. 

 Encystment with autogamy has been described for the intestinal parasites, and 

 in the Trypanosomes, parasitic in blood, conditions similar to those of the 

 Haemosporida seem to occur. The transfer of the parasite from host to host is 







Fig. 139. — Leucozyto:iocm ziemanni (after Schaudinn). a-c, growth and multi- 

 plication of nuclei in ookinete, in intestine of mosquito ; d, transformation of ripe ookinete 

 into Spirochsete; e, division of Leucozytozoon. 



accomplished by blood-sucking animals; insects (mosquitos, flies, lice, etc.) for 

 mammals and fjirds; leeches (Piscicola) for fishes. Fertilization very probably 

 takes place in the intermediate host. The following account, doubtful in 

 several points, is given for Trypanosoma (Leucozytozoon) ziemanni. After the 

 parasite has multiplied rapidly for some time in the blood of the owl, some 



Fig. 140. Fig. 141. Fig. 142. 



Fig. 140. — Lamblia inlesiinalis (aitei Giassi). Front and side views, h, nucleus. 

 Fig. 141. — Trichomonas batrachoriim (after Dobell). ax, axial rod; cs, cytostome; 

 b, blepharoplast; m, undulating membrane; n, nucleus. 

 Fig. 142. — SpirochcEta pallida (after Schaudinn). 



become macrogametes and others form eight microgametes. Macro- and 

 microgametes unite in the intestine of the mosquito, Culex pipiens, to a zygote 

 (ookinete), which grows to a large multinucleate body (fig. 139, a-c). From 

 this, together with the formation of a residual body (cf. Sporozoa) numerous 

 young flagellates arise, which are transferred by the bite of the mosquito to a 

 new host. 



