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PROTOZOOLOGY 



Family 3 Pleuronematidae Kent 



Genus Pleuronema Dujardin. Ovoid to ellipsoid; peristome begins 

 at anterior end and extends for 2/3 the body length ; a conspicuous 

 membrane at both edges; semicircular swelling to left near oral area; 

 no cytopharynx; close striation longitudinal; one to many posterior 

 sensory stiff cilia; macro nucleus round or oval; a micro nucleus; a 

 contractile vacuole; trichocysts in some species; fresh or salt water, 

 also commensal in freshwater mussels. 



P. crassum D. (Fig. 292, a). 70-120/x long; somewhat compressed; 

 Woods Hole (Calkins). 



Fig. 292. a, Pleuronema crassum, X240 (Kahl); b, P. anodontae, X290 

 (Kahl); c, d, P. setigerum, X540 (Noland); e, P. coronatuni, X540 

 (Noland); f, P. marinum, X400 (Noland); g, Cyclidium litomesurn, X300 

 (Stokes); h, Cristigera phoenix, X500 (Penard); i, C. media, X400 (Kahl). 



P. anodontae Kahl (Fig. 292, b). About 55^ long; posterior cilium 

 about 1/2 the body length; in Sphaerium, Anodonta. 



P. setigerum Calkins (Fig. 292, c, d). Ellipsoid; flattened; ventral 

 surface slightly concave; about 25 ciliary rows; 38-50m long (No- 

 land); in salt water; Massachusetts, Florida. 



P. coronatum Kent (Fig. 292, e). Elongate ovoid; both ends equally 

 rounded; caudal cilia long; about 40 ciliary rows; 47-75/1 long 

 (Noland); in fresh and salt water; Florida. 



