HOLOTRICHA 713 



form in salt water is said to possess often long caudal cilia. 



P. griseus Claparede and Lachmann. Oblong; 165-200/i long; 

 fresh water. 



Genus Pseudoprorodon Blochmann. Similar to Prorodon; usually 

 flattened; one side convex, the other concave; ectoplasm conspicu- 

 ously alveolated; trichocysts grouped; 1 or more contractile vacu- 

 oles posterior-lateral or distributed, with many pores; macronucleus 

 elongate; cytopharynx with trichites; fresh or salt water. 



P. farctus (Claparede and Lachmann) (Figs. 304, m). Ellip- 

 soid; cytostome surrounded by long trichites; contractile vacuole 

 posterior, with secondary vacuoles; macronucleus elongate; body 

 150-200/x long; fresh water. 



Genus Coelosomides Anigstein (Coelosoma A.). General appear- 

 ance similar to Prorodon and Holophrya; body cylindrical; ciliation 

 uniform; at anterior end, a conspicuous ciliated vestibule runs down 

 deep; mouth and cytopharynx; endoplasm vacuolated; a macronu- 

 cleus and a micronucleus; marine. 



C. marina A. (Fig. 304, n, o). About 200/x long; central endoplasm 

 highly vacuolated; periphery finely reticulated; macronucleus elon- 

 gate; micronucleus compact (Anigstein, 1911; Faure-Fremiet, 1950). 



Genus Placus Cohn (Spathidiopis Fabre-Domergue ; Thoraco- 

 phrya Kahl). Body small; ellipsoid or ovoid; somewhat compressed; 

 pellicle with conspicuous spiral furrows; cytostome a narrow slit at 

 anterior extremity; with strong cilia on right margin of slit; cytopyge 

 a long narrow slit with cilia on both sides; macronucleus ellipsoid 

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

 fresh water. 



P. socialis (Fabre-Domergue) (Fig. 304, p, q). 40-50/* by 28-32/t, 

 about 22^ thick; salt water; Florida (Noland, 1937). 



Genus Lacrymaria 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 (Miiller) (Fig. 305, a). Elongate; highly contractile; 2 

 macro nuclei; 2 contractile vacuoles; extended forms 400-500/* 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. 305, b). Body flask- 

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

 tracted; macronucleus short sausage-like or horseshoe-shape; endo- 



