Phylum Protoplasta [ 159 



rather massive extranuclear body regularly present in the cell and distinct both 

 from the centrosome and the blepharoplast. In the present group, it divides when 

 the nucleus does. Thus this group, although marked chiefly by characters which are 

 negative or derived, appears possibly to be natural. 



1. Flagella two. 



2. Cells not notably slender Family 1. CERCOMONADroA. 



2. Cells notably slender Family 2. TRYPANOPLASMroA. 



1. Flagellum one. 



2. Not regularly markedly amoeboid Family 3. Oicomonadacea. 



2. Conspicuously amoeboid Family 4. CHAETOPROXEroA. 



Family 1. Cercomonadida [Cercomonadidae] Kent Man. Inf. 1: 249 (1880). 

 Family Bodonina Butschli in Bronn Kl. u. Ord. Thierreichs 1: 827 (1884). Family 

 5oc?onflccag Senn in Engler and Prantl Nat. Pflanzenfam. I Teil, Abt. la: 133 (1900). 

 Family Bodonidae Doflein Protozoen 73 (1901). Family Cercobodonidae Hollande 

 1942. Family Proteromonadidae Grasse Traite Zool. 1, fasc. 1: 694 (1952). Non- 

 pigmented flagellates, the bodies not notably slender, with two flagella, one directed 

 anteriorly, the other trailing. Fischer (1894) found both of the flagella of Bodo to 

 be acroneme. 



In Bodo both flagella are free of the body. There are numerous species, in infusions 

 or foul or polluted waters, or entozoic in a wide variety of animals, from insects to 

 men. Prowazekia, Proteromonas, and Pleuromonas are doubtfully c'istinct. Rhyncho- 

 monas, from fresh or foul waters, is distingished by a protoplasmic beak in which 

 the anterior flagellum is imbedded. Cercomonas, of like habitats, has the trailing 

 flagellum grown fast to the cell membrane; the eel! : exhiljit a considerable capacity 

 to send out lobopodia. 



Biflagellate organisms which can lose their flagella and take on the appearance 

 of ordinary amoebas have repeatedly been discovered and variously named. So far as 

 the pseudopodia are lobopodia and the flagella are unequal, these organisms belong 

 in this family; but many accounts fail to establish the equality or inequality of the 

 flagella, with the result that the names used in them cannot be applied with confidence. 

 This is true of various organisms originally named under Pseudospora, Dimastiga- 

 moeba, and Naegleria. The earliest generic name definitely applicaple to organisms 

 as described in Cercobodo Senn, 1910. 



Belar (1914, 1916, 1920, 1921), Kuhn (1915), and others have described mitosis 

 in various examples of this family; the most detailed account is of Bodo Lacertae in 

 Belar's paper of 1921. The flagella spring from a blepharoplast from which a rhizo- 

 plast extends into the nucleus. The chromatin is reticulate, not massed in a karyo- 

 some, but no centrosome has been recognized in it when it is not dividing. The 

 rhizoplast, where it passes through the cytoplasm, is surrounded by stainable Ring- 

 korper. The parabasal body, located on the posterior side of the nucleus, is massive 

 and often irregular. In division, the blepharoplast divides, each part retaining one 

 flagellum and generating an additional one. The rhizoplast appears to begin to split, 

 but presently it and the Ringkorper become invisible. Within the intact nuclear mem- 

 brane there appears a spindle with evident centrosomes at the poles. The centrosomes 

 come presently to the inner surface of the nuclear membrane, while the blepharo- 

 plasts move to adjacent positions on the outside. Chromosomes duly assemble at 

 the equator of the spindle and undergo division. Division of the nucleus is com- 

 pleted by constriction of the nuclear membrane; the parabasal body undergoes 

 constriction; the cell divides by constriction lengthwise. The Ringkorper and the 

 rhizoplast are apparently regenerated by the blepharoplast. 



