24 SPOROZOA. 



forms-^ i.v., male and female — may, however, multiply by fission. 

 The three types become fully differentiated only in the inverte- 

 brate host. The males are of more slender form than the females, 

 and have a longer free flagellum. Parthenogenesis occurs in the 

 females. The sexual forms conjugate : this may take place in 

 the blood of the vertebrate, but it is abortive. True maturation 

 takes place in the gut of the invertebrate host. 



t^jiirocluiiiii. — These are closely related to the former, but they 

 resemble very minute slender threads, wavy or spirally twisted 

 in form, and have a narrow undulating membrane, but no 

 flagella (fig. 4, b). There are several important parasites in 

 this group : one, H. ohermeieri (Cohn), produces human relaps- 

 ing fever in Africa, and is carried by Ticks ; another, S. gaUin- 

 armii (Marchoux and Simond), produces spirillosis in fowls in 

 8. America. European relapsing fever is apparently carried by 

 the Bed Bug {Cinie.r), Fowl Spirochaetes especially by Ticks 

 of the genus Argas. 



CLASS III. SPOROZOA. 



Another very important group of protozoa parasitic in both 

 vertebrate and invertebrate auimals is the class of Sporozoa 

 (fig. 5). These protozoa are capable of producing serious 

 pathological disturbances, often leading to death. 



There are three orders in this class. 



The order Grei/arinoiilea are only parasitic in invertebrate 

 animals, and need no further notice. 



Another order of Sporozoa are called CoceiiJiida, which trans- 

 form themselves into egg-shaped zoosperms by the formation of 

 a capsule and the production of several large spores from their 

 granular contents. 



The third order are the Hii'inon/inn'Jfn. 



l)i.'ica.-<i'-jirodiir/ni/ Sporo::<>a. — Four well-known maladies are 

 produced in birds, animals, and man by these low forms of life 

 ■ — namely, coccidioiiix, or " liver-i'ot," in the rabbit ; pgorofjier- 



