SPOROZOA 431 



Eimeria (Coccidium) Schubergi.— This cocjcidium occurs in 

 the intestine of a common myriapod (thousand-legged worm), 

 Lithobius fmficatus. It is the organism in which Schaudinn 

 worked out the life-cycle now regarded as typical for Eimeriadae,. 

 and which corresponds very closely to that of E. siiedcs. (See 

 Fig. 80, page 162). 



Hsemoproteus Columbae. — Celli and Sanfelice in 1891 ob- 

 served this organism in the red blood cells of doves. It is widely 

 distributed as a parasite of wild doves and has been found in 

 Europe and in North and South America. • The life-history of the 

 parasite in the vertebrate host and its mode of transmission by 

 flies of the genus Lynchia has been most fully studied by Aragoa.^ 

 In the circulating blood of doves the organism is most commonly 

 seen as a large crescent-shaped structure occupying most of the 

 interior of an erythrocyte and crowding the nucleus of the latter 

 to one side or encircling it. The outline of the erythrocyte and 

 the outline of its nucleus are not distorted. The parasites are 

 definitely recognizable as females and males, macrogametocytes 

 with granular, deeply staining cytoplasm and microgametocytes 

 with a paler cytoplasm. When these are ingested by the fly along 

 with its blood meal, the gametes arise, fertilization takes place 

 and there is produced a creeping ookinete which apparently does 

 not penetrate the intestinal wall in the fly or indeed undergo any 

 further development there. It gains the blood stream of a new 

 host, especially young nestlings, when the fly bites them. It is 

 taken up by a leukocyte which comes to rest in the pulmonary 

 capillaries of the young bird. Here the parasite produces a very 

 large cyst and divides to form very numerous minute sporozoits. 

 When the cyst bursts these sporozoits gain the blood stream, 

 penetrate erythrocytes and grow to produce the gametocytes 

 again. The asexual cycle of schizogony seems to be lacking. 



This organism is important as a typical example of Hcemo- 

 proteus, as it is the one species of this genus in which the life cycle 

 has been most completely studied. 



' Archivj. Protistenkunde, 1908, Bd. XII, S. 154-167. 



