54 



PEOTOZOA 



FAMILY 3. CHLAMYDODONTIDAE. 



Ovoid or kidney-shaped Infusoria with the mouth usually some dis- 

 tance from anterior end; gullet specially modified to swallow food of 

 large size: about 11 genera. 



1. NASSULA Ehrenberg. Body ovate or cylindrical; mouth between 

 middle and anterior end; gullet armed with rods or with a membrane: 

 8 species; in fresh and salt water. 



N. ornata Ehr. Body nearly circular, usually with brightly colored 

 spots; gullet with rods; length .2 mm.: in fresh water. 



N. macrostoma Cohn (Fig. 84) . Body nearly circular, with brightly 

 colored spots; gullet with a membranous lining; length .05 mm.: 

 marine; Woods Hole. 



2. CHILODON Ehrenberg. Body flattened, with convex dorsal side; 



Fig. 84 Fig. 85 Fig. 86 



Fig. 84 Nassula macrostoma (Calkins). Fig. 85 Chilodon cucullulus (Calkins). 

 Fig. 86 Frontonia leucas (Calkins). 



mouth at or in front of middle of body; gullet armed with rods: 

 6 species; in fresh and salt water. 



C. cucullulus (0. F. Miiller) (Fig. 85). Length .1 mm. or less; 

 body ovoid; forward end bent to the left: in fresh and salt water. 



FAMILY 4. CHILIFEEIDAE. 



Mouth never behind the middle and always open, with an undulating 

 membrane on the edge of it or in the slightly developed gullet: 

 9 genera. 



Key to the genera of Chiliferidae here described : 



! Long ventral furrow leading back from the mouth 1. FRONTONIA 



a 2 No such furrow. 



&! Caudal bristle present 3. UEONEMA 



& 2 No bristle. 



Cj Body oval, symmetrical 2. COLPIDIUM 



c 2 Body rounded dorsally, straight ventrally 4. COLPODA 



1. FRONTONIA Ehrenberg. Body large, ellipsoid or elongate and 

 contractile and colorless, or green or brown, with mouth near forward 



