572 PROTOZOOLOGY 



a long narrow slit with cilia on both sides; macro nucleus ellipsoid 

 to sausage-form; contractile vacuole posterior; salt, brackish or 

 fresh water. 



P. socialis (Fabre-Domergue) (Fig. 271, n, o). 40-50/i by 28-32^, 

 about 22/i thick; salt water; Florida (Noland). 



Genus Lacr3miaria Ehrenberg. Polymorphic; cylindrical, spindle- 

 or flask-shaped; with a long contractile proboscis; cytostome round; 

 ciliary rows meridional or spiral to right; near cytostome a ring-like 

 constriction with a circle of longer cilia ; cytopharynx usually dis- 

 tinct; contractile vacuole terminal; fresh or salt water. Numerous 

 species. 



L. olor (Muller) (Fig. 272, a). Elongate; highly contractile; 2 

 macronuclei; 2 contractile vacuoles; extended forms 400-500m up 

 to 1.2 mm. long; when dividing, long neck is formed sidewise so that 

 it appears as oblique division (Penard) ; fresh and salt water. 



L. lagenula Claparede and Lachmann (Fig. 272, b). Body flask- 

 shape; neck highly extensible; striation distinct, spiral when con- 

 tracted; macro nucleus short sausage-like or horseshoe-shape; endo- 

 plasm granulated; body 70^ long, up to ISO/u (Kahl); salt water. 



L. coronata C. and L. (Fig. 272, c). Large; neck extensible; body 

 form variable, but usually with bluntly rounded posterior end; endo- 

 plasm appears dark; striae spiral; 85-100^1 long; salt and brackish 

 water. 



Genus Enchelys Hill. Flask-shape; anterior end obliquely trun- 

 cate; cytostome slit-like, rarelj'- round; fresh or salt water. Several 

 species. 



E. curvilata (Smith) (Fig. 272, d). Elongate ovoid; posterior end 

 rounded; longitudinal striation; macronucleus band-form; contrac- 

 tile vacuole terminal; endoplasm yellowish, granulated; about 150ju 

 long; fresh water among algae. 



Genus Crobylura Andre. Body when extended spindle-form, with 

 truncate ends; when contracted, thimble-form; cilia short and thick; 

 several long caudal cilia; slit-like cytostome at anterior end; no 

 apparent cytopharynx; macronucleus irregularly rounded, hard to 

 stain; micronucleus not observed; contractile vacuole latero-pos- 

 terior; fresh water. One species. 



C. pelagica A. (Fig. 272, e). Body 65-95^ long; in freshwater 

 plankton. 



Genus Microregma Kahl. Small, ovoid; dorsal side convex; 

 ventral side flat; with a small slit-like cytostome near anterior end; 

 with or without caudal bristle; fresh or salt water. 



M. (Enchelys) auduhoni (Smith) (Fig. 272, /). Body plastic; 



