ANIMAL PARASITES 



71 



actively moving, tadpole-shaped organisms. Under high power, 

 study a less active specimen. Cut down the light and note the 

 three anteriorly projecting flagella and the posteriorly directed 

 flagellum attached to the body of the organism by an undulating 

 membrane. A wave of movement from the anterior to the pos- 

 terior end of the flagellum and membrane simulates a series of 

 minute projecting legs. At the anterior end, near the base of the 

 flagella, is a small cytostome; while through the center of the 

 body there runs a hyaline rodlikc structure, the axostyle. 



tntmcyt tet //— 



pair h 



post.tl—l 



Fig. 23. — Ventral view and cyst of Giardia lamblia. (Aftev. Kofoid and Swezy.) 



In stained specimens note the above-described structures and, 

 particularly, the blepheroplast from which the flagella originate, 

 the chromatic basal rod, and the nucleus. (Cf. Fig. 22.) The 

 oval cysts with remains of the fibrillar apparatus will be demon- 

 strated. Those of the species infecting man have not been found 

 and it is generally believed that this species is transferred in the 

 trophozoite stage. 



Giardia lamblia (Fig. 23) is a remarkable parasite infecting 

 man. In the older literature it is known as Lamblia intestinalis 

 and hence the term lambliasis, as well as giardiasis, is applied 

 to the infection. Occasionally it is transferred from man to 



