New American Infusoria. By Dr. A. C. Stokes. 701 



Heteromita Sphagni, sp. no v. Fig. 17. 



Body elongate ovate, smooth, about four times as long as broad, 

 somewhat depressed; anterior border acutely pointed, the posterior 

 rounded, the posterior region flattened ; one lateral i)order convex, 

 the opposite flattened, nearly straight ; flagella subequal in size and 

 length, each about twice as long as the body, inserted at the anterior 

 apex of the zooid ; contractile vesicle single, conspicuous, situated in 

 the posterior body-half, near the flattened lateral border; nucleus 

 represented by a circular light spot near the posterior extremity, in 

 the median line. Length of body 1/750 in. Habitat : Standing 

 pond water, with Sphagnum. 



Seteromita nasuia, sp. nov. Fig. 18. 



Body ovate, smooth, somewhat depressed, very slightly change- 

 able in form, about twice as long as broad, the posterior extremity 

 rounded, the anterior produced into a stout, undulating flagellum less 

 than one-half as long as the zooid ; posterior or trailing flagellum 

 slender, about twice as long as the body, arising from the ventral 

 surface at some distance from the frontal border ; contractile vesicle 

 apparently single, situated near the anterior extremity ; nucleus pre- 

 sumably subcentrally located. Length of body 1/4500 in. Habitat : 

 Standing pond water, with decaying Sphagnum. 



This form is readily recognizable by the peculiar and characteristic 

 condition of the anterior flagellum. This appendage is thick, stout, 

 and apparently a continuation of the apical extremity of the body. It 

 presents much the appearance of a comparatively robust, vibratile, 

 proboscidiform prolongation. In a few instances it has been observed 

 to become thickened by a temporary outflow of sarcode from the 

 body, 



Heteromita parvifilum, sp. nov. Fig. 19. 



Body ovate, smooth, slightly changeable in form, less than twice 

 as long as broad, the posterior extremity rounded, the anterior obtusely 

 pointed; flagella subequal, less than one-half as long as the body; 

 contractile vesicles two, situated side by side, at the anterior extremity ; 

 nucleus broadly ovate or subspherical, subcentrally located ; endoplasm 

 granular, especially at the posterior extremity. Length of the body 

 1/3000 to 1/2250 in. Habitat : A vegetable infusion. 



Tetramitus frondarius, sp. nov. Fig. 20. 



Body very soft and changeable in form, normally elongate, sub- 

 cylindrical, about three times as long as broad, the posterior border 

 obtusely pointed, the anterior truncate and often centrally emar- 

 ginate ; flagella in length somewhat exceeding the width of the body, 

 originating close together near the centre of the frontal margin; 

 nucleus apparently subspherical, situated in the anterior body-half; 



