PROTOZOOLOGY 



Fig. 156. a, Trinema enchelys, X330 (Wailes); b, Placocista spinosa, 

 X200 (Wailes); c, AssuUna seminulum, X400 (Wailes); d, Nebela 

 collaris, x200 (Cash); e, Quadrula symmetrica, X200 (Cash); f, Sphe- 

 noderia tenia, X330 (Leidy). 



Genus Quadrula Schulze. Test pyriform, hemispherical, or dis- 

 eoidal; with quadrangular siliceous or calcareous platelets, ar- 

 ranged generally in obhque series, not overlapping; a single nu- 

 cleus; body and pseudopodia similar to those of Difflugia; fresh 

 water. 



Q. symmetrica (Wallich) (Fig. 156, e). Compressed, smaller 

 platelets near aperture; cytoplasm very clear, with chlorophyllous 

 granules; 3-5 pseudopodia digitate; nucleus posterior; 80-140ju 

 by 40-96ai; in sphagnum. 



Genus Sphenoderia Schlumberger. Test globular or oval, some- 

 times slightly compressed; hyaline, membranous, with a short 

 broad neck, and a wide elliptical aperture; scales circular, oval, 

 or hexagonal, arranged in alternating series; cytoplasm colorless; 

 1-2 contractile vacuoles; filopodia, fine, branching; fresh water. 



S. lenta S. (Fig. 156, /). Hyahne test ovoid or globular; scales 

 circular or broadly oval; aperture terminal, surrounded by a thin 

 chitinous collar, one side inclined inwards; nucleus large; cyto- 

 plasm colorless; 2 contractile vacuoles; 30-64/^ by 20-46m; aper- 

 ture 10-22/z in diameter. 



Cash, J. 1905, 1909 

 ozoa. Vols. 1, 2. 



References 



The British freshwater Rhizopoda and Heli- 



