26 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [BuU. 



i6. Like Euglena in shape and method of contraction; 

 secondary flagelhnn small, close to chief flagellum 



Astasia* 

 Oval or elongated; secondary flagellum commonly 



directed backwards Zygoselmis 



ly. Elongated or crescentic; with four acute, longitu- 

 dinal ridges, and hence nearly four-sided 



Sphenomonas"^ 

 Like the above, but without the longitudinal ridges. . 



Clostonema* 

 Nearly ellipsoidal, with many slightly spiral ridges. . 



Tropidoscyphus 



Description of Genera. 



Cryptoglena Ehrbg. ^ Chloromonas S. K. 



Rigid, flattened, with two lateral green chromato- 

 phores, a single eye-spot, a mouth, and vacuole system. 

 Nucleus posterior. 



C. pigra Ehrbg., Fig. 93. 

 Euglena Ehrbg. 



Large flagellates, spindle-formed or elongated, widely 

 variable; usually with a strong, spirally marked cuticle. 

 Frequently the whole animal moves with a screw-like 

 motion. Body very flexible. Chromatophores green, 



either disk-shaped and numerous, or star-shaped or rib- 

 bon-like, and in small numbers; commonly without pyre-, 

 noids. In many species the animals are colored red ; less 

 frequently there are found quite colorless individuals. 

 Mouth and pharynx evident, and a long flagellum arising 

 from the mouth which, however, frequently drops off. At 

 the lower end of the pharynx is a vacuole system with an 

 eye-spot close by. Nucleus present, as well as paramylum 

 bodies. 



En. viridis Ehrbg., Fig. 45. 



En. sp. (?), Fig. 50. 



En. dcses Ehrbg., Fig. 51. 



En. spirogyra Ehrbg., Fig. 56. 



En. sp. (?), Fig. 57. 



En. sp. (?), Fig. 52. This animal is sufficiently flexible to 

 bend from side to side, but does not show the peculiar 



