HAEMOSPORIDIA 615 



workers the erythrocytes into which merozoites enter are often the 

 most immature erythrocytes (polychromatophilic erythroblasts). 

 The species of avian Plasmodium are transmitted by adult female 

 mosquitoes belonging to Culex, Aedes or Theobaldia. Some of the 

 common species are briefly mentioned here. Avian Plasmodium 

 (Manwell, 1935a; Hewitt, 1940b); avian hosts (Wolfson, 1941); dis- 

 tribution (Man well and Herman, 1935; Herman, 1938; Hewitt, 

 1940a; Wood and Herman, 1943). 



P. relictum Grassi and Feletti (P. praecox G. and F. ; P. inconstans 

 Hartman) (Fig. 264, a). In English sparrow (Passer domesticus) and 

 other passerine birds, also in mourning doves and pigeons (Coatney 

 1938); schizogony varies in different strains, in 12, 24, 30 or 36 

 hours; 8-15 or 16-32 merozoites from a schizont; gametocytes 

 rounded, with small pigment granules; host-cell nucleus displaced; 

 canaries (Serinus canaria) susceptible; many strains; transmitted by 

 Culex, Aedes and Theobaldia; widely distributed. Duration of infec- 

 tion (Manwell, 1934; Bishop, Tate and Thorpe, 1938); variety 

 (Manwell, 1940); in Culex pipieris (Huff, 1934); development in 

 birds (Mudrow and Reichenow, 1944); relationship of E.-E. and 

 erythrocytic stages (Sergent, 1949). 



P. vaughani Novy and McNeal (Fig. 264, b). In robin (Turdus 

 m. migratorius) and starling (Sturnus v. vulgaris) ; 4-8 (usually 4) 

 merozoites from a schizont, ordinarily with 2 pigment granules; 

 schizogony in about 24 hours; gametocytes elongate; host-cell nu- 

 cleus not displaced. 



P. cathemerium Hartman (Fig. 264, c). In English sparrow, cow- 

 bird, red-winged blackbird, and other birds; schizogony in 24 hours, 

 segmentation occurs at 6-10 p.m.; 6-24 merozoites from a schizont; 

 mature schizonts and gametocytes about 7-8ju in diameter; gameto- 

 cytes rounded; haemozoin granules in microgametocytes longer and 

 more pointed than those present in macrogametocytes; canaries 

 susceptible; numerous strains; common; transmitted by many spe- 

 cies of Culex and Aedes (Hartman, 1927). Relapse (Manwell, 1929); 

 acquired immunity (Cannon and Taliaferro, 1931) ; in ducks (Hegner 

 and West, 1941); cultivation (Hewitt, 1939); effect of plasmochin 

 (Wampler, 1930). 



P. rouxi Sergent, Sergent and Catanei (Fig. 264, d). In English 

 sparrow in Algeria; similar to P. vaughani; schizogony in 24 hours; 

 4 merozoites from a schizont; transmitted by Culex. 



P. elongatum Huff (Fig. 264, e). In English sparrow; schizogony 

 occurs mainly in the bone marrow, and completed in 24 hours; 8-12 

 merozoites from a schizont; gametocytes elongate, found in periph- 



