26; 



in size takes place, and eventually they become spherical 

 and divide into a number of segments (schizonts). 

 According to some observers segmenting forms are only 

 found in the spleen. 



(ii) Sexual Forms. Free in the plasma, twelve 

 to fifteen /* long. These are male and female, and are 

 characterized by the same general differences as other 

 gametes ; the male mikrogametocyte is slender and 

 finely granular ; the female makrogametocyte is fat 

 and coarsely granular. 



(iii) A mikrogamete in the form of a small mass 

 of chromatin separates off and fertilizes the (now) 

 makrogamete. 



Fig. 81. H. ranarum (or Drepanidium ranarum) young form, 



Gametes free in the Plasma, and Fission forms in 



Spleen. (Partly after Minchin) 



(iv) A zygote results, which is at first motile. 

 This becomes encysted as the 



(v) Oocyst, which is found in the epithelial cells 

 of the intestine. This passes out eventually in the 

 faeces of the frog. Sporoblasts are formed as in the 

 malarial cycle, and from these result 



(vi) Sforozoits. These would gain access to a 

 fresh frog which had swallowed an oocyst. 



According to Billet development takes place in 

 leeches of the genus Helobdella. 



