12 



TROPICAL MEDICINE AND HYGIENE 



(4) Hcemogregarinida are, by many authors, included 

 in the Hceniosporidia. The young forms are found in 

 red corpuscles of reptiles (fig. 3), and in a few instances 

 in red blood corpuscles of mammals, as in the 

 Indian rat and the African jerboa. They may also be 

 found in leucocytes, as in the dog and in the palm 

 squirrel. Older forms moving like gregarines are found 

 free in the blood plasma. Sporulation takes place in cells 

 of solid viscera, such as the liver and in the bone-marrow. 

 It appears to be doubtful what are the definitive hosts ; 



FIG. 3. Hsemogregarines of frog. 



in the dog hcemogrcgariue, the host, is an ioxdina. The 

 parasites do not form pigment, and differ from the 

 hcemosporidia, in the restricted sense, in the structure of 

 the nucleus of the young parasite. The nucleus stains 

 with basic stain, and the chromatin is distributed in fine 

 granules throughout the nucleus. Segmentation does not 

 take place whilst the parasites are present in the blood. 

 No h'cemogregarines are known to occur in man, and it is 

 only recently that they have been found in mammals and 

 birds (fig. 3). 



(B) Only a portion of the protoplasm of the cell 

 divides into spores. The parent protozoon still remains 

 alive, further growth takes place, and again, part of the 



