MASTIGOPHORA, CHRYSOMONADINA 267 



chromatophores ; a single nucleus; oil drops and leucosin; holophytic. 

 Taxonomy and phylogeny (Schiller, 1925, 1926; Conrad, 1928a; 

 Kamptner, 1928; Deflandre, 1952a). 



Examples : 



Pontosphaera haeckeli Lohmann (Fig. 109, a). 

 Discosphaera tubifer Murray and Blackman (Fig. 109, b). 



Family 5 Silicoflagellidae Borgert 



Exclusively marine planktons; with siliceous skeleton which en- 

 velops the body. Example: Distephanus speculum (Miiller) (Fig. 109, 

 c) (Deflandre, 1952). 



Suborder 2 Rhizochrysidina Pascher 



No flagellate stage is known to occur; the organism possesses pseu- 

 dopodia; highly provisional group, based wholly upon the absence of 

 flagella; naked or with test; various forms; in some species chroma- 

 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. 109, d; 110, a, b). 10-14/* in diameter; 1-2 

 chromatophores: branching rhizopods; fresh water. 



Genus Chrysidiastrum Lauterborn. Naked; spherical; often sev- 

 eral in linear association by pseudopodia; one yellow-brown chro- 

 matophore; fresh water. 



C. catenation L. Cells 12-14ju in diameter (Pascher, 1916a). 



Genus Chrysarachnion Pascher. Ameboid organism; with achro- 

 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 (Pascher, 1916a). 



C. insidians P. (Fig. 110, c, d). Highly amoeboid individuals 3-4/x 

 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 



