TELOSPORIDIA 



67 



process of each asexual generation is completed in forty-eight hours. 

 The parasite of quartan fever (Plasmodium malarice) is smaller in size ; 

 it does not cause the red blood cor- 

 puscles to swell ; it forms only 6 to 

 12, and generally 8, merozoites; and 

 the asexual form takes seventy-two 

 hours to complete its cycle. 



To cultivate the stages which 

 develop in the mosquito, a tempera- 

 ture of 25 to 30 C. must be main- 

 tained. Human malaria germs de- 

 velop in Anopheles, and Proteosoma 

 in Gulex pipiens. A period of nine 

 days is required for the completion 

 of schizogony. Mosquitoes should 

 be examined by the method already 

 described. 



FIG. 19. Proteosoma prcecox. (After 

 Hartmann.) a, Merozoite. 6, Macro- 

 gametocyte. c, Microgamete. Magni- 

 fied about 2,250 : 1. 



Class IV. Telosporidia. 



The class Telosporidia is composed of two orders, the Coccides 

 and the Gregarines. They are closely related and are purely parasitic 

 in their habits. The alternation of generation in the malaria parasite 

 is so strikingly analogous to that which occurs in the Coccides, that 

 the Hsemosporides have always, up to the present, been included as 

 a third order of the Telosporidia. They differ, however, in several 

 essential particulars from these, more especially in the absence of 

 enclosed sex-forms and in the motile character of the copula. 

 Enclosed reproductive bodies (sporocysts or pseudo-navicellse) , con- 

 taining, rarely one and generally several, long, thin germs (sporozoites) , 

 are peculiarly characteristic of both the Coccides and the Gregarines, 

 although the method of their development is not the same in the 

 two orders. The Aggregata are usually classed as Gregarines, but 

 it is highly probable that they should form a third order of Telo- 

 sporidia, quite distinct from the other two. For this reason the 

 description of them is appended as a note to the Gregarines. 



schizont. 5 6, Nuclear division within the schizont. 7, Breaking up of the schizont 

 into merozoites. 8, Single merozoites, one of which (left arrow) enters a blood corpuscle 

 and develops into a schizont (3 7). After a certain period of infection the sex-forms 

 develop : 9a 12a, Macrogametocytes. 9b 12b, Microgametocytes. If the macrogameto- 

 cytes remain in the blood-stream of man, they multiply by parthenogenesis and form 

 schizonts (I3c 17c). Below the dotted line the stages which take place in the gut of 

 Anopheles are shown : 13a14a, Maturation of the macrogametes. 13b14b, Formation 

 of the microgametes. 15b, A microgamete. 16, Copulation. 17, Motile copula or 

 "ookinet." 18, Ookinet penetrating the intestinal wall of the mosquito. 19, Ookinet 

 passing through the epithelium. 20 25, Sporogony upon the outer surface of the intes- 

 tinal wall. 26, Passage of the sporozoites to the salivary gland. 27, Salivary gland of 

 mosquito containing sporozoites. 



