EIMBRIA. 173 



cells of the small intestine. Young schizonts possess eight to 

 twelve nuclei, and schizogony results in producing the same 

 number of merozoites. Each merozoite is spindle-shaped, 

 and carries a pair of hyaline blades or laminae at its anterior end, 

 which help it to enter the epithehal cell. The male gametocyte 

 shows a large niunber of nuclei situated towards its periphery, 

 and the mature microgametes are found to cluster round 

 a residual mass of cytoplasm. The macrogametocyte is 

 distinguished by its size and by the presence of darkly staining 

 granules in its cytoplasm ; its posterior end shows a short 

 recurved tail ; the nucleus at an early stage is spherical and 

 contains a karyosome, but when mature becomes elongated, 

 and the karyosome breaks up into a number of small, irregularly 

 scattered granules. Oocysts are subcyhndrical, disporocystid, 

 and tetrazoic, and develop outside the host. There is no 

 oocystic residuum, and the oocystic membrane has a double 

 contour. Sporocysts have their long axis directed at right 

 angles to the long axis of the oocysts ; a sporocystic residuum 

 is present. 



Dimensions. — ^Trophozoites, young 10 /x by 3 /x ; schizonts, 

 young 20-25 ;u,; merozoites 12ju, by Sju, ; microgametes 

 2-4)u, by 1-5 /x ; macrogametes 16-20 /x by ll-14)u. ; oocysts 

 16-20 ju. by 11-14/x ; sporocysts 8/x by 4ju.. 



Habitat. — In the small intestine of the toad, Bufo melano- 

 stictus Schneider : Bengal, Calcutta. 



103. Isospora sp. 



"flsospora sp., Cooper & Gulati, 1926, pp. 191-2. 



Oocysts of an unidentified species of Isospora were found in 

 the faeces of a heifer calf at Dhupatal, of a bull calf and two 

 cows at Tocklai, and of a heifer at Shillong, in Assam. 



Oocysts were quite round, and within twenty-four hours 

 two fully formed sporoblasts were seen in all cases. 



Habitat. — ^Ahmentary canal of cows : Assam, Dhupatal, 

 Tocklai, and Shillong. 



Subfamily EIMERIIN.E Wenyon, 1926. 



Oocysts contain four sporocysts, each containing two, four, 

 or many sporozoites. 



Genus EIMERIA Aime Schneider, 1875. 



Gregarina, Eimer, 1870, p. 4. 

 Eimeria, Aime Schneider, 1875 a, pp. xl-xlv. 

 Psorospermium, Rivolta, 1878. 

 Coccidium, Leuckart, 1879, p. 254. 

 Orthospora, Aime Schneider, 1881, p. 389. 



