234 



FRESH-WATER BIOLOGY 



160 (159) Body amoeboid; endoplasm red or brown. 



Vampyrella Cienkowsky. 

 Representative species. . . Vampyrella lateritia Cienkowsky 1865. 



Body spherical or elongated. Pseudopodia arising from all parts of the 

 body or from one point. The nucleus and contractile vacuole usually con- 

 cealed by the contents of the endoplasm. A gelatinous sheath sometimes 

 surrounds the body. Habitat among algae upon which it feeds. Diameter 

 25 to 80 p. 



FIG. 353. Vampyrella lateritia. X 250. (After Conn.) 



161 (i) Pseudopodia with axial filaments Class Actinopoda. 



Fresh-water species included in one subclass. 



Subclass Heliozoa . . 162 

 No central capsule between endoplasm and ectoplasm. Pseudopodia ray-like. 



162 (165) With no external envelop .... Order Aphrothoracida . . 163 



163 (164) Nucleus single. 



Representative species. 



. . . . Actinophrys Ehrenberg. 

 Actinophrys sol. Ehrenberg 1830. 



Body' spherical with protoplasm highly vacuolated. Usually 

 one contractile vacuole which rises and pushes out the surface as 

 a rounded globule before bursting. Pseudopodia extending from 

 all parts of the body. Habitat pond water among aquatic plants; 

 very common. Diameter 40 to 50 M- 



FIG. 354. Actinophrys sol. cv, contractile vacuole. X 245. (After Leidy.) 



164 (163) Nuclei many Actinosphaerium Stein. 



Representative species. 



Actinosphaerium eichhornii Ehrenberg 1840. 



Protoplasm vacuolated with very large vacuoles about the 

 periphery. Nuclei scattered throughout the endoplasm. Pseudo- 

 podia extending from all parts of the body. One or more con- 

 tractile vacuoles. Habitat among aquatic plants. Not common. 

 Average diameter 200 to 300 /* Some have reported individuals 

 over 1000 n in diameter. 



FIG. 355. Actinosphaerium eichhornii. cv, contractile vacuole. 

 (After Leidy.) 



X40. 



165 (162) With an external envelop 166 



166 (167) Envelop gelatinous, without plates or spicules. 



Order Chlamydophora. 



One genus reported in North America. . . . Actinolophus Schultze. 



With a pedicel. 

 Representative species. . . Actinolophus minutus Walton 1905. 



Pseudopodia very short, extending from all parts of the body. Nucleus single, in 

 the posterior region. Contractile vacuole not observed. Diameter of body with en- 

 velop 12 n. Length of pedicel 70 /u. Habitat river water. Described by Walton 

 from Ohio. This genus is introduced provisionally. Further knowledge is needed 

 concerning it, as certain species referred to the genus show marked affinities with 

 Suctoria. 



FIG. 356. Actinolophus minutus. cv, contractile vacuole; . nucleus. X 350. (After Walton.) 



