504 



TELOSPORIDIA 



gested that the parasite breaks up into a large number of minute 

 elements, each of which possesses a chromatin granule. These 

 elements grow and become rods, which are set free by rupture of 

 the enclosing sphere, and so fill the endothelial cells, from which 

 they escape also by rupture. The rods are looked upon as gameto- 

 cytes, rather than merozoites, and are considered to be the forms 

 seen in the red cells. 



Comparison.— The organism is believed to resemble Theileria 

 parva. 



Inoculations.— Attempts to transmit the parasite to inoculated 

 animals failed. The animals used Were rabbits and monkeys. 



Cultivation. — -So far the organism has not been cultivated. 



Transmission by Insects. — -Experiments have been performed with 

 the mosquito Phalangomyia dehilis Dyar and Knab, but no evidence 

 of the presence of the parasites in the stomach or salivary glands 

 could be obtained. 



Pathogenicity. — It is believed to be the causal agent of Oroya fever. 



Family Plasmodid^ Luhe, igo6. 



Synonyms. — Gymnosporidia Labbe, 1894; Acytosporidia Wasie- 

 lewski, 1896; Hcemamcehidce Ross, 1899; Acytosporea Minchin, 1903. 



Definition.— Hcemosporidia with hsemozoin. The trophozoite 

 grows into the schizont, containing haemozoin, which breaks up into 

 a number of merozoites, which are usually said never to be flagellate. 

 The ookinete encysts and forms a typical oocyst, which breaks 

 up eventually into sporozoites. 



Classification. — The genera of the Plasmodidae are: Plasmodium 

 Marchiafava and Celli, 1885; Lavemnia Grassi and Feletti, 1889; 

 Hcemocystidium Castellani and Willey, 1904. 



These genera may be distinguished as follows:— 



A. Size large. Schizogony binary or at times quaternary, in 



general circulation — Hcemocystidium. 



B. Size small. Schizogony into more than four merozoites- — 



T Without crescent bodies — Plasmodium. 

 II. With crescent bodies^ — Laverania. 



Genus Plasmodium Marchiafava and Celli, 1885. 



Synonyms. — Oscillaria Laveran, 1881 ; Hcematomonas Osier, 1887 ; 

 Hcematophyllum Metchnikoff, 1887; HcBmamceha Grassi and Feletti, 

 1889; Laverania Grassi and Feletti, 1889; Cytamceha, DanileWski, 

 1890; Proteosoma Labbe, 1894; Hamosporidium Lewkowicz, 1897; 

 Cytosporon Wasielewski, 1901. 



Definition. — -Plasmodidae, in which the gametocytes resemble more 

 or less the schizonts by being round in shape. Schizogony in the 

 peripheral blood. 



Nomenclature. — -Some remarks are perhaps necessary on the 

 nomenclature. Laveran first used the term Oscillaria because he 

 saw the flagellate form, which at that time was thought to be a 



