CHAPTER XXI 



TELOSPORIDIA 



Telosporidia — -Gregarinida— Coccidiidea — Haemosporidia — Hsemogregarinidae 

 — ■ Toxoplasmidse — Piroplasmidas — Plasmodidse — ■ Haemoproteidae — - 

 References. 



PHYLUM in. TELOSPORIDIA Schaudinn, 1900. 

 Synonym. — Eimerioinea Poche, 1913. 



Definition. — Parasitic flasmodromata without motile organs, in 

 which the reproductive phase of the life-cycle, which produces spores, 

 is distinct from and follows after the trophic phase. 



Remarks. — 'All the Telosporidia are parasitic, and usually begin 

 their life-cycle as small amoeboid bodies, with a single nucleus, called 

 trophozoites, which absorb nutriment and grow, and when fully 

 developed show a cuticle, an ectoplasm, and an endoplasm. The 

 endoplasm is granular, and contains a vesicular nucleus with chro- 

 matin karyosomes. The nucleus of the fully-grown trophozoite 

 now begins to divide, and the parasite is known as a schizont, 

 which reproduces by spore-formation. These spores, called mero- 

 zoites, complete the cycle of asexual reproduction called schizogony. 

 At some stage in the life-history of the parasite, generally when 

 conditions of life are not favourable, some merozoites are produced, 

 which, instead of developing into trophozoites, become sexual 

 gametocytes, male and female. These forms, which are often resis- 

 tant, are the means of transmitting the given species from one host 

 to another. They produce gametes, which conjugate and form 

 bodies called sporoblasts, and, lastly, spores called sporozoites. 



Classification. — ^The Telosporidia are divided into three orders: 

 Gregarinida, Coccidiidea, and Haemosporidia, while the two latter 

 are often put together into the Coccidiomorpha. 



These may be recognized as follows : — • 



A. Only young trophozoites intracellular — -Gregarinida. 



B. Full trophozoite stage intracellular — Coccidiomorpha. 



'} I. With resistant spores in the sporocysts — Coccidiidea. 

 11. Without resistant spores in sporocysts — -Hcemosporidia. 



ORDER I. GREGARINIDA Lankester, 1866. 



^Synonyms. — Gregarinidea Lankester, 1885; Gregarince Haeckel, 1866, 

 ^ Definition. — Telosporidia, in which only the young trophozoites are intra- 

 cellular, the fully-grown forms being extracellular. * 



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