280 



FRESH-WATER BIOLOGY 



82 (81) Body elongate, nearly cylindrical, the anterior extremity truncate 



and slightly curved; a short, curved seta borne on either 

 side near the anterior end. A long, straight bristle extend- 

 ing from the posterior end. . . . Loxocephalus Kent. 

 Representative species. . Loxocephalus granulosus Kent 1882. 

 Endoplasm granular, mouth on the obhque anterior bor- 

 UMumliii^ujxu/,. der although quite indistinct. Nucleus spherical, central. 

 Contractile vacuole posterior. Length 40 to 70 (i. _ Often 

 abundant among decaying vegetable matter. Conjugation 

 readily occurs in infusions. 

 Fig. 494. Loxocephalus granulosus. X 375. (After Edmondson.) 



83 (80) Like Uronema, but with an anterior, spiral row of long cilia. 



hexiotricha Stokes. 

 Representative species. . . . Dexiotricha plagia Stokes 1885. 



Body about three times as long as broad, bearing minute 

 hemispherical protuberances. Cilia setae-like; a row of flexible 

 setae extending from the margin of the mouth obliquely across 

 the right-hand side of the anterior half of the body. Nucleus 

 subcentral; contractile vacuole posterior. Length 60 /n. Pond 

 water. 



Fig. 49s. Dexiotrkha plagia. X 315. (Alter Stokes.) 



84 (79) 

 8s (86) 



Without a posterior bristle. 



8S 



Ellipsoidal to elongate, somewhat acute behind. Mouth lateral, 

 surrounded by a furrow which extends backward. Pharynx 

 short with rods. . Frontonia Ehrenberg. 



Representative species Frontonia leucas Ehrenberg 1838. 



Body elongate-oval, wider anteriorly. Mouth a slit anterior to the 

 middle of the body. Cilia fine, in longitudinal rows. Contractile 

 vacuoles, usually two. Trichocysts numerous. Length 250 to 300 11. 

 Stagnant water. 



Fig. 496. 



Frontonia leucas. 

 V, vacuole. 



, canal; iV, macronucleus; «, micronucleus; 

 X i6s. (After Calkins.) 



86 (85) Ovate, flattened, rounded at each end. Mouth triangular or crescent- 

 shaped, lateral, in front of the middle of the body. 



Glaucoma Ehrenberg. 

 Representative species. Glaucoma scintillans Ehrenberg 1830. 



The vibratile membranes extending around the mouth pre- 

 senting a bilabial appearance. Nucleus large, central. Con- 

 tractile vacuole posterior. Length 75 ^t. Infusions. 



Fig. 497. Glaucoma scintillans. cv, contractile vacuole; macn, macro- 

 nucleus; mien, micronucleus. X 3S0. (After Butschli.) 





