INFUSORIA 



63 



0. bifaria Stokes (Fig. 112). Body broad; length .2 mm.; bristles 

 in a single line: in fresh water. 



9. STYLONYCHIA Ehrenberg. Body elliptical, 

 rigid; oral groove triangular or semicircular, reach- 

 ing middle of body ; cilia and bristles as in Oxytricha; 

 usually 3 long caudal bristles present: 

 6 species ; in fresh and salt water ; very 

 common, the animals often moving by 

 quick jerks. 



S. pustulata Ehr. Body broad; 

 length .25 mm.; width .1 mm.: in 

 infusions. 



S. mytilus (0. F. Miiller) (Fig. 

 113). Body broadest in front of 

 middle; length .3 mm.; in fresh 

 water. 



Fig. 112 



Oxytricha 

 Mfaria 

 (Conn). 



Fig. 113 



Stylonychia 

 mytilus (Doflein). 



FAMILY 2. EUPLOTIDAE. 



Cilia very little developed or absent; large bristles and spines char- 

 acterize the ventral surface; nucleus ribbon-shaped; body round or oval: 

 5 genera; mostly marine. 



Key to the genera of Euplotidae here described : 



! No posterior hook-like projection at side of body. 

 &! Anterior bristles present. 



c x About 9 anterior bristles 1. EUPLOTES 



c 2 About 6 anterior bristles 2. DIOPHBYS 



6 2 No anterior bristles 3. URONYCHIA 



o 2 Posterior hook-like projection at side of body 4. ASPIDISCA 



1. EUPLOTES Ehrenberg. Body oval 

 or round, either green or colorless; mouth 

 in the hinder half of body, a long arched 

 oral groove joining it with the front end 

 of the body; about 9 large bristles oppo- 

 site the groove and a similar number of 

 anal bristles : 5 species ; in fresh and salt 

 water. 



E. charon (0. F. Miiller) (Fig. 114). 

 Length .045 mm.: in fresh and salt 

 water. 



2, DIOPHRYS Dujardin. Like Euplotes except that about 6 anterior 

 and 8 anal bristles, all very long and thick, are present; movement rapid 

 and continuous, not by jumps: 2 species; marine. 



D. appendiculatus Stein (Fig. 115). Length .05 mm.; Woods Hole, 



Fig. 114 



Fig. 115 



Fig. 114 <E uplot es chevron 

 (Calkins). Fig. 115Diophrys 

 appendiculatus (Calkins). 



