212 ANNIE I'ORTKll. 



(4) The tlagellate forms are from 12 /x to 75 /i long, aud 

 lo lit to 2*8 /i broad (including the flagellum). The general 

 protoplasm is slightly alveolar. The nucleus is vesicular. 

 The blepharoplast is well marked, rod-like, usually anterior 

 to the nucleus, and generally homogeneous. 



Chromidia may occur as isolated granules. 



(5) The undulating membrane and Hagellum are well 

 marked. There are indications of niyonemes (PI. 12, figs. 40, 

 45) in some stained specimens, but the niyonemes are more 

 evident in some living specimens. The membrane is of great 

 use in securing smoothness of motion. The flagellum is long 

 and forms a chromatic edge to the membrane. A basal 

 granule may occur near the root of the tiagellum. 



(6) The post-Hagellate stage in the host's rectum (PI. 13, 

 figs. 97-114) gives rise to resistant (resting) bodies that are 

 passed out as cysts with the faeces and serve to infect new 

 hosts. The cysts measure, on the average, 4 ju by 2"5 fx. The 

 fiagellates divide, usually twice, and the four small forms 

 thus produced lose their fiagella, become round, and then 

 invested with a thin gelatinous wall. 



(7) The post-flagellate stages in the ova and puparia of 

 Melophagus (PI. 13, figs. 57-94) serve for the hereditary 

 transmission of C. melophagia. The flagellates pass 

 through the wall of the gut near the anterior ends of the 

 ovaries, swarm towards and enter the ovaries and penetrate 

 the ova — the posterior (aflagellar) end of the parasite being 

 used in penetration. Within the ova each parasite loses its 

 flagellum and becomes ovoid or rounded (PI. 13, figs. 64-73). 

 Nuclear multiplication follows aud " plasmodial " forms ai-e 

 produced (PI. 13, figs. 74r-77). These give rise to small, 

 rounded bodies (PI. 13, tigs. 83, 84) about 3 )u by 2 ^ which 

 undergo multiple fission to form rosettes (PI. 13, fig. 88), 

 which give rise to the typical pre- flagellates. 



(8) The young Melophagus do not show flagellates until 

 after their first feed of blood, the blood stimulating the pre- 

 flagellates to form flagella. 



(9) Multiplication of C. melophagia by longitudinal 



