HOLOTRICHA 585 



Tribe 3 Hypostomata Schewiakoff 



Without furrow; free-living; conspicuous oral or pharyngeal basket 

 Ciliation complete; dorsal cilia usually less dense than those on ventral 



surface Family 1 Nassulidae 



Ciliation incomplete; dorsal surface without cilia or with a few sensory 

 bristles 

 Posterior ventral surface with a style. .Family 2 Dysteriidae (p. 586) 



Without a style Family 3 Chlamydodontidae (p. 588) 



Furrow from anterior end of cytostome; parasitic 



Family 4 Pycnothricidae (p. 590) 



Family 1 Nassulidae Schouteden 



Genus Nassula Ehrenberg. Oval to elongate; ventral surface flat, 

 dorsal surface convex; usually brightly colored, due to food mate- 

 rial; cytostome 1/3-1/4 from anterior end; body often bent to left 

 near cytostome; opening of oral basket deep, in a vestibule with a 

 membrane; macronucleus spherical or ovoid, central; a single micro- 

 nucleus; contractile vacuole large, with accessory vacuoles and opens 

 ventrally through a tubule-pore; fresh or salt water. Many species. 



N. aurea E. (Fig. 278, a). 200-250^ long; fresh and brackish water 

 (Kahl). 



Genus Paranassula Kahl. Similar in general appearance to Nas- 

 sula; but with preoral and dorsal suture line; longer caudal cilia on 

 dorsal suture; pharyngeal basket not funnel-like, with 16-18 trichites; 

 about 75 ciliary rows; trichocysts especially in anterior region. 



P. microstoma (Claparede and Lachmann) (Fig. 278, h). Pellicle 

 roughened by a criss-cross of longitudinal and circular furrows; 

 macronucleus elongate oval, posterior; contractile vacuole near mid- 

 dle and right-dorsal; about 80-95/1 long; salt water; Florida (Noland). 



Genus Cyclogramma Perty. Somewhat resembling Nassula; but 

 conspicuous oral basket in pyriform depression and opens toward left 

 on ventral surface; depression with a short row of small membranes 

 at its anterior edge; trichocysts usually better developed than in 

 Nassula; fresh water. 



C. trichocystis (Stokes) (Fig. 278, c). Body colorless or slightly 

 rose-colored; trichocysts thick and obliquely arranged; one con- 

 tractile vacuole; usually full of blue-green food vacuoles; actively 

 motile; about 60/i long; in fresh water among algae. 



Genus Chilodontopsis Blochmann. Elongate ellipsoid; colorless; 

 ventral surface flattened, dorsal surface slightly convex; both sides 

 ciliated; oral basket without vestibule; cytostome with a mem- 

 branous ring; usually with a postoral ciliary furrow; fresh water. 



