696 



ORDER: DIPLOMONADIDA 



anterior lateral blepharoplasts with the granules on the nuclear membranes, 

 but he is not convinced that these fibres are continued to the karyosomcs 

 of the nuclei (Fig. 290). 



The nuclei are two ovoid bodies which lie one on each side of the 

 middle line of the body near its ventral surface in the region of the sucking 

 disc. Each consists of a nuclear membrane, within which is a karyosome, 

 usually elongate in form. In what appear to be older individuals, several 

 separate chromatin masses united by a meshwork of fibres are present. 



Fig. 292. — Giardia intestinalis : Various Stages of Division (x ca. 6,0UO). 

 (After Wenyon and O'Connor, 1917.) 



On the anterior surface of the membrane adjacent to the blepharoplasts 

 is the granule mentioned above. 



The flagellates multiply by a complicated process of longitudinal 

 division. So seldom are division stages of the free flagellates encountered 

 that most observers consider that the process occurs usually in the encysted 

 condition. It seems probable that changes in the nuclei and blepharo- 

 plasts take place preparatory to division, which is completed within the 

 cyst. The writer and O'Connor (1917) and Kofoid and Swezy (1922) 

 obtained preparations of G. intestinalis of man which showed undoubted 



