32 CONNECTICUT GEOL. AND NAT. HIST. SURVEY, [BuU. 



Heteronema Duj. 



Like Anisonenia, but with second flagellum larger and 

 point of origin somewhat more posterior; body with ob- 

 lique mouth depresison. 

 H. sp. ( ?), Fig. 94. Fig. 94a is side view. Of the generic 

 identification of this animal I am in doubt. 

 Entosiphon Stein. 



Similar to Anisonenia. Ventral side with a strong 

 medial furrow. Both flagella arise in a slight depression 

 in the anterior end. The trailing flagellum is directed 

 backwards and is not so well developed as in Anisonenia. 

 Pharynx ver}'^ long, extending to the hind end of the body ; 

 protrusible. Contractile vacuole, secondary vacuoles, and 

 a nucleus present. 

 En. sulcatus Duj., Fig. 89. 



SUB-ORDER ISOMASTIGODA 



Key to Genera. 



1. Solitary 2 



Colonial 19 



2. Uncolored 3 



Colored 11 



3. With two flagella 4 



With four flagella 7 



4. Body laterally expanded into two wings, each with a 



flagellum Trepomonas* 



Body not laterally expanded 5 



5. Body sometimes attached by a stalk; not flattened, 



and with no cuticle Aniphinionas* 



Body never attached by a stalk; with a cuticle 6 



6. Body much flattened, anterior end oblique; pharynx 



not evident Cyathomonas* 



Body less flattened, and with an evident pharynx. . . . 



Chilomonas* 

 Body ellipsoidal, not flattened; pharynx not evident, 



but with a well-developed cuticle Polytoma* 



7. With a deep ventral furrow Collodictyon 



Without ventral furrow 8 



