482 PROTOZOOLOGY 



pods (ticks, mites), micro- and macro-gametes develop and unite in 

 pairs; zygotes become oocysts which increase in size and produce 

 sporoblasts, spores, and sporozoites. 



H. muris (Balfour) (Fig. 223, n). In various species of rat; several 

 specific names were proposed on the basis of difference in host, 

 locality, and effect on the host, but they are so indistinctly defined 

 that specific separation appears to be impossible. Schizogony in the 

 liver of rat; young gametocytes invade mononuclear leucocytes and 

 appear as haemogregarines ; when blood is taken in by the mite, 

 Laelaps echidninus, union of 2 gametes produces vermicular body 

 which penetrates gut-epithelium and reaches peri-intestinal tissues 

 and grows; becoming surrounded by a cyst-membrane, cyst content 

 breaks up into a number of sporoblasts and then into spores, each of 

 which contains a number of sporozoites; when a rat devours infected 

 mites, it becomes infected. 



Genus Karyolysus Labbe. Sporoblasts formed in the oocysts in gut- 

 epithelium of a mite, vermiform sporokinetes, enter host ova and 

 become mature; when young mites hatch, spores in gut-epithelium 

 are cast off and discharged in faeces; a lizard swallows spores; liber- 

 ated sporozoites enter endothelial cells in which schizogony takes 

 place; merozoites enter erythrocytes as gametocytes which when 

 taken in by .a mite complete development in its gut. 



K. lacertarum (Danilewsk}^) (Fig. 223, o). In Lacerta muralis; 

 sexual reproduction in Liponyssus saurarum; sporokinetes 40-50/z 

 long; spores 20-25^ in diameter. 



References 



Becker, E. R. 1934 Coccidia and coccidiosis. Ames, Iowa. 



BouGHTON, Ruth B. and J. Volk 1938 Avian hosts of the genus 

 Isospora (Coccidiida). Ohio. Jour. Sci., Vol. 38. 



Christensen, J. F. 1938 Species differentiation in the coccidia 

 from the domestic sheep. Jour. Parasit., Vol. 24. 



CoNNAL, A. 1922 Observations on the pathogenicity of Isospora 

 hominis, Rivolta^ emend. Dobell, based on a second case of hu- 

 man coccidiosis in Nigeria, with remarks on the significance of 

 the Charcot-Leyden crystals in the faeces. Trans. Roy. Soc. 

 Trop. Med. Hyg., Vol. 16. 



Dobell, C. 1925 The life-history and chromosome cycle of Aggre- 

 gata eherthi. Parasitology, Vol. 17. 



Hardcastle, a. B. 1943 A check list and host index of the species 

 of the protozoan genus Eimeria. Proc. Helm. Soc. Washington, 

 Vol. 10. 



Hauschka, T. S. 1943 Life history and chromosome cycle of the 

 coccidian Adelina deronis. Jour. Morph., Vol. 73. 



