210 PROTOZOOLOGY 



tophores are entirely lacking, so that the organisms resemble some 

 members of the Sarcodina. Several genera. 



Genus Rhizochrysis Pascher. Body naked and amoeboid; with 1-2 

 chromatophores : fresh water. 



R. scherffeli P. (Figs. 93, d; 94, a, h). 10-14/i in diameter; 1-2 

 chromatophores : branching rhizopods ; fresh water. 



Genus Chrysidiastrum Lauterborn. Naked; spherical; often sev- 

 eral in linear association by pseudopodia; one j^ellow-brown chro- 

 matophore; fresh water. 



C. catenaium L. Cells 12-14)u in diameter. 



Genus Chrysarachnion Pascher. Ameboid organism; with a chro- 

 matophore, leucosin grain and contractile vacuole; many individuals 

 arranged in a plane and connected by extremely fine rhizopods, the 

 whole forming a cobweb network. Small animals are trapped by the 

 net; chromatophores are small; nutrition both holophytic and holo- 

 zoic; during division the chromatophore is often unevenly distrib- 

 uted so that many individuals without any chromatophore are 

 produced; fresh water. 



C. insidians P. (Fig. 94, c, d). Highly amoeboid individuals 3-4^ 

 in diameter; chromatophore pale yellowish brown, but becomes blu- 

 ish green upon death of organisms; a leucosin grain and a contractile 

 vacuole; colony made up of 200 or more individuals. 



Genus Chrysothylakion Pascher. With retort-shaped calcareous 

 shell with a bent neck and an opening; shell reddish brown (with 

 iron) in old individuals ; through the aperture are extruded extremely 

 fine anastomosing rhizopods; protoplasm which fills the shell is 

 colorless; a single nucleus, two spindle-form brown chromatophores, 

 several contractile vacuoles and leucosin body; marine water. 



C. vorax P. (Fig. 94, e,f). The shell measures 14-18/x long, 7-10/x 

 broad, and 5-6/x high; on marine algae. 



Suborder 3 Chrysocapsina Pascher 



Palmella stage prominent; flagellate forms transient; colonial; 

 individuals enclosed in a gelatinous mass; 1-2 flagella, one chromato- 

 phore, and a contractile vacuole; one group of relatively minute 

 forms and the other of large organisms. 



Genus Hydrurus Agardh. In a large (1-30 cm. long) branching 

 gelatinous cylindrical mass; cells yellowish brown; spherical to 

 ellipsoidal; with a chromatophore; individuals arranged loosely in 

 gelatinous matrix; apical growth resembles much higher algae; mul- 

 tiplication of individuals results in formation of pyrimidal forms 



