HAEMOSPORIDIA 



619 



H. columbae Celli and Sanfelice (Fig. 266). In pigeons (Columba 

 livid), etc.; widely distributed; young schizonts, minute and uninu- 

 cleate, are in the endothelial cells of lungs and other organs, grow 

 into large multinucleate bodies which divide into 15 or more uninu- 

 cleate cytomeres (Aragao). Each cytomere now grows and its nucleus 

 divides repeatedly. The host cell in which many cytomeres undergo 

 enlargement, becomes highly hypertrophied and finally ruptures. 

 The multinucleate cytomeres break up into numerous merozoites, 

 some of which possibly repeat the schizogony by invading endothe- 

 lial cells, while others enter erythrocytes and develop into gameto- 

 cytes which are seen in the peripheral blood; sexual reproduction 



Fig. 266. The life-cycle of Haemoproieus columbae. (Several authors), 

 a, a sporozoite entering an endothelial cell of the pigeon; b, growth of a 

 schizont; c, segmentation of multinucleate schizont into uninucleate 

 cytomeres; d-i, development of cytomeres to produce merozoites; j-m, 

 development of microgametes; n-p, development of macrogamete; q, 

 fertilization; r, s, ookinetes; t, a young oocyst in the stomach wall of 

 a fly; u, a ruptured mature oocyst with sporozoites. a-k, n, o, in the 

 pigeon, 1, m, p-u, in Pseudolynchia maura. 



