94 (93) At least some of cilia in bipolar rows. Macronuclei small, vesicular 95 



94 (93) Ciliary rows in a ventral band about one-half cell width, extending about 

 four-fifths cell length. Macronucleus single, large, C-shaped. Family 

 CRATERISTOMATIDAE. 



95 (9^) Body contractile and snakelike in shape. Cytostome circular. 

 CHELOCERCIDAE, in part (also see couplet 10). 



Family TRA- 



95 (94) Cell length less than 50 fim, humped dorsally. Cytostome anterior 

 and slitlike. Family STEPHANOPOGONIDAE. 



96 (93) Cytostome on concave left edge of body, preceded by hooklike lateral ex- 

 tension. Nuclei vesicular. No contractile vacuole. Family LOXODIDAE. 



96 (93) Cytostome on convex left edge. Macronuclei one to several, not vesic- 

 ular. One to several contractile vacuoles. Family AMPHILEPTIDAE. 



35 



