66 



THE INVERTEBRATA 



backward and united to the body by an undulating membrane ; a cyto- 

 stome near the broad anterior end; and an axostyle which projects 

 from the posterior end. The united basal granules act as a division 

 centre, possibly in virtue of a centriole concealed among them. The 

 cytostome is used for ingestion. A staining body which follows the 

 base of the undulating membrane has been regarded as the parabasal 

 body, but a deeper-lying structure is now asserted to represent that 



Fig. 50. Trichomonas niuris, semidiagrammatic. From Hegner and TaHa- 

 ferro, after Wenrich. axs. axostyle; ce. compound basal granule which acts 

 as a centriole; ch.gr. inner row of chromatic granules; ch.gr.' outer row of 

 chromatic granules; ch.rd. chromatic basal rod of undulating membrane; 

 ch.rg. chromatic ring at the emergence of the axostyle ; fl. anterior flagella ; 

 fl,.' posterior flagellum; kar. karyosome; M. mouth (cytostome); nu. nucleus; 

 p.hy. parabasal body; u.me. undulating membrane; u.me.' posterior flagellum 

 lying along the edge of the undulating membrane. 



organ. In the cytoplasm, a number of " chromatic granules " are also 

 present. Several species, parasitic in various cavities of vertebrates, 

 including the mouth, intestine, and vagina of man. 



Hexamitus { = Octomitus, Fig. 4). (Diplomonadina.) Body elon- 

 gate ; without gullet ; presenting strong bilateral symmetry ; and bear- 

 ing on each side four flagella, three anterior and one posterior, the 

 basal granules of the foremost being united; and an axostyle. Two 

 nuclei are present, one on each side of the body, near the anterior 



