334 PROTOZOOLOGY 



and anastomosing, colorless; nucleus inconspicuous; one or more 

 contractile vacuoles, small ; fresh water. 



P. mutabilis C. (Fig. 155, /). Resting form 90-100ai in diameter; 

 extended forms (including pseudopodia) 300-400jU long. 



Genus Hyalodiscus Hertwig and Lesser. Discoid, though outline 

 varies; endoplasm reddish, often vacuolated and sometimes shows 

 filamentous projections reaching body surface; a single nucleus; 

 ectoplasmic band of varying width surrounds the body completely; . 

 closely allied to Vampyrella ; fresh water. 



H. ruhicundus H. and L. (Fig. 155, g). 50-80^ by about 30^; 

 polymorphic; when its progress during movement is interrupted by 

 an object, the body doubles back upon itself, and moves on in 

 some other direction; freshwater ponds among surface vegetation. 



References 



Cash, J. 1905 The British freshwater Rhizopoda and Heliozoa. Vol. 



1. London. 

 DoBELL, C. 1913 Observations on the life-history of Cienkowski's 



Arachnula. Arch. f. Protistenk., Vol. 31. 

 DoFLEiN, F. and E. Reichnow 1929 Lehrbuch der Protozoenkunde. 



Jena. 

 DuBOSCQ, 0. 1921 Labyrinthomyxa sauvageaui n. g., n. sp., pro- 



teomyxee parasite de Laminaria lejolisii Sauvageau. C. r. soc. 



biol., Paris. Vol. 84. 

 KtJHN, A. 1926 Morphologie der Tiere in Bildern. H. 2; T. 2. 



Rhizopoden. 

 Leidy, J. 1879 Freshwater Rhiozopods of North America. Report 



U. S. Geol. Survey. Vol. 12. 

 RosKiN, G. 1927 Zur Kenntnis der Gattung Pseudospora Cienkow- 



ski. Arch. f. Protistenk., Vol. 59. 

 Valkanov, a. 1940 Die Heliozoen und Proteomyxien. Ibid., Vol. 



93. 

 Young, E. L. 1943 Studies on Labyrinthula, the etiologic agent of 



the wasting disease of eel-grass. Amer. Jour. Bot., Vol. 30. 

 ZoPF, W. 1887 Handhuch der Botanik (A. Schenk). Vol. 3. 



