POLYMASTIGINA 313 



frogs, also in midgut of Trutta fario and in rectum of Motella tricir- 

 rata and M. mustela in European waters, 



H. salmonis (Moore) (Fig. 147, d). 10-12^ by 6-8^; in intestine 

 of various species of trout and salmon; schizogony in epithelium of 

 pyloric caeca and intestine; cysts; pathogenic to young host fish 

 (Davis, 1925). 



H. periplanetae (Belaf). 5-8^ long; in intestine of cockroaches. 



H. cryptocerci Cleveland (Fig. 147, e). 8-13m by 4-5.5^1; in Crypto- 

 cercus punctulatus. 



H. meleagridis McNiel, Hinshaw and Kofoid. Body 6-12^1 by 

 2-5ju. It causes a severe catarrhal enteritis in young turkeys. Experi- 

 mentally it is transmitted to young quail, chicks, and duckling. 



Genus Giardia Kunstler {Lamblia Blanchard). Pyriform to ellip- 

 soid; anterior end broadly rounded, posterior end drawn out; bi- 

 laterally symmetrical; dorsal side convex, ventral side concave or 

 flat, with a sucking disc in anterior half; 2 nuclei; 2 axostyles; 8 

 flagella in 4 pairs; cysts oval to ellipsoid; with 2 or 4 nuclei and 

 fibrils; in the intestine of various vertebrates. Several species. 



G. intestinalis (Lambl) {G. lamblia Stiles) (Fig. 148). When the 

 flagella lash actively, the organism shows a slight forward movement 

 with a sidewise rocking motion. The trophozoite is broadly pyriform, 

 not plastic; 9-20^ by 5-10/x; sucking disc acts as attachment organ- 

 ella; cytoplasm hyaline; 2 needle-like axostyles; 2 vesicular nuclei 

 near anterior margin; 8 flagella in 4 pairs; two flagella originate 

 near the anterior end of axostyles, cross each other and follow the 

 anterolateral margin of the disc, becoming free; two originating in 

 anterior part of axostyles, leave the body about 1/3 from the pos- 

 terior tip; two (ventral) which are thicker than others, originate in 

 axostyles at nuclear level and remain free; two (caudal) flagella arise 

 from the posterior tips of axostyles; a deeply staining body may be 

 found in cytoplasm. 



The cysts are ovoid and refractile; 8-14ju by 6-10)u; cyst wall thin; 

 contents do not fill the wall; 2 or 4 nuclei, axostyles, fibrils and fla- 

 gella are visible in stained specimens. 



This flagellate inhabits the lumen of the duodenum and other 

 parts of small intestine of man. Both trophozoites and cysts are or- 

 dinarily found in diarrhoeic faeces. In severe cases of infection, an 

 enormous number of the organisms attach themselves to the mucous 

 membrane of the intestine which may result in abnormal functions 

 of the host tissues. In some cases, the flagellate has been reported 

 from the gall bladder. The stools often contain unusual amount of 

 mucus. But there is no evidence that G. intestinalis attacks the in- 

 testinal epithelium. 



