No. 2.] FRESH-WATER PROTOZOA. 35 



or far apart. One or two contractile vacuoles and a 

 nucleus. 

 Am. sp. (?), Fig. 117. This is a form found very abun- 

 dantly, but, so far as seen, never attached as in the typical 

 species of Amphimonas. The two equal flagella would 

 seem to place it here. 

 Trepomonas Duj. 



Somewhat spherical or flattened, with two mouths on 

 opposite sides of the body. The two sides are prolonged 

 into wings projecting posteriorly. These wings are con- 

 tracted near the body so that a cross section of the animal 

 is in the form of an S. In the anterior end of each wing 

 arises a long flagellum directed forward ; also three very 

 small secondary flagella. Nucleus anterior, contractile 

 vacuole posterior. 

 T. agilis Duj., Fig. 115. 

 Cyathomonas From. 



Much flattened, somewhat oval, with an obHquely 

 truncated anterior end, bearing two equal or nearly equal 

 flagella. Parallel with the anterior border is a row of 

 highly refracting bodies. Contractile vacuole anterior, 

 nucleus central. 

 Cy. tnmcata From., Fig. iii. 



Cy. sp. (?), Fig. 112. The lower figure shows a side view. 

 Chilomonas Ehrbg. 



Somewhat oval, contracted posteriorly ; laterally com- 

 pressed. Anterior end obliquely notched. Upon the upper 

 side of the notch arise two flagella. The mouth leads into 

 a tube-like pharynx extending to the middle of the body. 

 Colorless, with an anterior contractile vacuole and a pos- 

 . terior nucleus. 

 Ch. Paramecium Ehrbg., Fig. 91. An extremely common 



species. 

 Ch. sp. ( ?), Fig. 95. A smaller type with differently shaped 

 body, far less common than the first species. It may be 

 only a variety of the more common species. 

 Polytoma Ehrbg. 



Mostly ellipsoidal, with a delicate shell and two fla- 

 gella ; colorless ; occasionally a slightly colored eye-spot. 



