?8 DISEASES OF RABBITS 



zoites after invading the cells become trans-r 

 formed into male and female elements, respec- 

 tively termed microgametes and macrogametes. 

 The maerogamete develops slowly from the 

 merozoite. Its nucleus contains a karyosome, 

 which later becomes expelled. The granules of 

 its protoplasm become ranged around the peri- 

 phery and form an enveloping membrane with 

 a micropyle. At this stage it is ovoid in form 

 and escapes from the cell and lies on the sur- 

 face of the epithelium and is ready for fertiliza- 

 tion. 



The microgamete is produced in a slightly 

 different manner. The merozoite loses its en- 

 veloping membrane and granular protoplasm. 

 Its nucleus contains a large karyosome. The 

 nucleus by subdivision becomes split up into a 

 number of daughter nuclei which become flat- 

 tened, elongated and comma-shaped and finally 

 develop two flagella. The microgametes, which 

 bear a great resemblance to the spermatozoa 

 of the higher animals, become detached from 

 the parent merozoite, which in this stage is 

 called a microgametocyte, and become free 

 moving organisms. Chemotaxic influence of 

 the maerogamete attracts a microgamete which 

 enters the micropyle of the maerogamete and 

 fertilizes it. The taicropyle closes immediately 

 the microgamete has entered so that only one 

 male element is concerned in fertilization. The 



