32 



PROTOZOA. 



The following three families of the Isomastigoda are separated as a sub-order 

 named Phytomastigoda on account of their plant-like features. 



Sub-order 5. PHYTOMASTIGODA. 



Holophytic, vegetable-like Isomastigoda with chlorophyll, without mouth. 

 Fam. 17. Chrysomonadina. Solitary or colonial ; rarely with test ; with 

 two, rarely one, brown to greenish -brown chromatophore ; usually with eye-spot 

 at the base of flagella ; colonies free-swimming, with spherical grouping of 

 individuals. Stylochrysalis Stein ; Chrysopyxis Stein ; Nephroselmis Stein ; 

 Synura Ehrb., colonial, with cuticle often growing 

 out inltf) fine spines ; Syncrypta Ehrb. 



Fam. 18. Chlamydomonadina. Almost always 

 green on account of considerable, usually single, 

 chromatophore ; usually delicate membranous shell 

 without large opening ; one to two contractile 

 vacuoles at base of flagella ; usually one eye-spot 

 (stigma). Reproduce by continued division within 

 the shell-membrane ; usually forming macro- and 

 microgonidia ; mostly solitary. Hymcnomonas 

 Stein : Chlorangiuin Stein ; Chlorogonium Ehrb. ; 

 Polytoma Ehrb., saprophytic, without chromato- 

 phores, with amylum bodies ; Chlamydomonas 

 Ehrb. ; Hamatococcus Agardh. ; Spondylomorum 

 Ehrb., colonial; Coccomonas Stein; Phacotus 

 Perty. 



Fam. 19. Volvocina. Biflagellate colonial 

 Phytomastigoda, intermediate in structure between 

 Chlamydomonas and Hcematococcus. Reproduction 

 by continued division of all, or of certain, indi- 

 viduals of the colony (parthenogonidia] to form 

 daughter colonies. In some, probably in all, con- 

 jugation occurs between definite individuals of the 

 colony, with or without differentiation of the 

 colonies and gametes into male and female. The 

 result of conjugation is a resting zygote, which 

 develops later into one or into several new colo- 

 FIG. 26. Codosiga botrytis (after nies. Gonium 0. F. Mtiller (Fig. 24), colonies of 

 Butschli). a, colony, b, one f our or sixteen individuals united to a quadran- 

 individual. K collar; nnu- } plate . like group . reproduction by simul- 

 cleus ; Cv contractile vacuole ; & , J 



Nv oral vacuole. taneous division of all the individuals to form 



daughter colonies ; Stcphanosph&ra Cohn ; Pan- 



dorina Bory de Vincent; Eudorina Ehrb.; Volvox L., spherical colonies with 

 numerous individuals, which are placed at equal distances within the common 

 thick colonial membrane, and lie in special membranes which stand off from 

 the cells and are compressed against one another into the form of hexagons. 



Order 2. CHOANOFLAGELLATA. 



Mastigopliora with a collar-like process of protoplasm round the 

 base of the single flagellurn. 



Solitary and colonial forms are included in this group. The 



