SPOROZOA 



47 



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body composed of melanin pigment, and then enter other corpuscles; 



spore-formation occurs every seventy-two hours or oftener, and is 



accompanied by a chill in the patient followed by a fever; if the blood 



is drawn into the intestine of a mosquito of the genus Anopheles certain 



of these spores produce flagellate individuals {micro g ametes) , and others 



produce rounded spores {macro gametes) ; these two 



conjugate, and motile individuals {zygotes) are the 



result, which penetrate the intestinal mucous mem- 

 brane and form large cysts on its outer surface; 



here they spoiTilate and develoiD finally into long, 



slender sporozoites which migrate into the body 



cavity and then into the salivary glands of the 



mosquito and are injected with the saliva into the 



blood of the next person the mosquito bites: 



3 species. 



P. malariae (Laveran) (Fig. 69). The cause 



of quartan malaria, in which the chill and fever 



occur every seventy-two hours. 



P. vivax Grassi and Feletti. The cause of the tertian malaria in 



which the chill and fever occur every forty-eight hours. 



P. falciparum Welch. The cause of pernicious or autumnal malaria 



in which the chill and fever occur every twenty-four hours, or irregularly. 



2. Babesia Starcovici {Pyrosoma Smith 

 and Kilbourne; Piroplasma Patton). An intra- 

 corpuscular parasite of mammalian blood- 

 corpuscles, without melanin pigment; trans- 



Fig. 69 — Plasmodi- 

 um malariae (Doflein). 

 The 6 circles represent 

 blood corpuscles into 

 which the parasite has 

 entered (A), where it 

 grows until it fills the 

 corpuscle (E) and 

 finally breaks up into 

 about 8 spores (F), 

 the whole process oc- 

 cupying 72 hours. 



O® Q® 



Fig. 70 — Babesia hige- 

 mina (Doflein). The 8 cir- 

 cles represent blood corpus- 

 cles containing the parasite. 



mission by the bite of ticks in whose intestine 

 the pseudosexual processes occur: many 

 species. 



B. hominis (Manson) . The cause of Rocky 

 Mountain spotted fever in man, the tick involved being Dermacentor 

 venustus. 



B. bigemina (Smith and Kilb.) (Fig. 70). The cause of Texas fever 

 in cattle, the tick involved being Margaropus {Boophilus) annulatus. 



Subclass 2. NEOSPORIDIA. 



Sporozoa which form sporocysts throughout life, the entire cell not 

 being used in the formation of spores: 4 orders. 

 Key to the orders of Neosporidia here described : 



«! In the organs of fishes and insects 1. Myxospoeidiida 



Cj In the muscle fibres of vertebrates 2. SARCOSPORlDlir#> 



