268 SOME MINUTE ANIMAL PARASITES 



B. coliy and possesses a larger cytopharynx. It seems 

 to be a much less common parasite than B. coli. 



Nyctotherus is a genus of Ciliates with bean or 

 kidney shaped bodies, possessing a large, curved 

 cytopharynx. Nyctotherus faba and N. giganteus 

 have been found in man, but many have been 

 described from the intestines of Amphibia and 

 insects. N. faba (Fig. 51) is about T V mm - l n g> an d 



has fine ordinary cilia 

 on one side of its mouth, 

 and thick forms (cirri) 

 on the other. A 7 , gigan- 

 teus, which has been 

 found in the dejecta of 

 typhoid patients, may be 

 as much as f mm. long 

 and /Q- mm - broad. It 

 encysts in the faeces, and 

 each new cyst produces 

 four new parasites. 



Probably one of the 

 most interesting Cili- 

 ates, at least to the 

 fisherman, is the fish 

 parasite, Ichthyophthirius. The organism is probably 

 of more trouble to the owners of aquaria or fish 

 hatcheries than it is in the open, but even there it 

 has been known to do much damage, especially in 

 heavily stocked waters. Wherever the fish are 

 collected in numbers, then the mortality increases by 

 leaps and bounds should a single specimen infected 

 with Ichthyophthirius be introduced. It attacks 



FIG. 51 NYCTOTHERUS FABA 

 The Ciliate as it occurs in man 



