Phylum Protoplasta [161 



AlexeiefF (1924) described fusions of pairs of cells of Bodo edax. 



Family 2. Trypanoplasmida [Trypanoplasmidae] Hartmann and Jollos 1910. Fam- 

 ily Cryptobiidae Poche in Arch. Prot. 30: 148 (1913). Family Trypanophidae Hol- 

 lande in Grasse Traite Zool. 1, fasc. 1: 680 (1952). Organisms of essentially the 

 structure of Cercomonas, but notably slender in adaptation to parasitic life, the 

 trailing flagellum forming the margin of an undulating membrane on the body. 

 Parasitic in various invertebrates and in the gut and blood of fishes. 



The numerous species may be included in a single genus Cryptobia Leidy [Try- 

 panoplasma Laveran and Mesnil; Trypanophis Keysselitz). 



According to Martin's (1910) description of a species from the eel Conger niger, 

 both flagella spring from a blepharoplast ("basal granule") at the anterior end. 

 As preliminary to division, the blepharoplast and flagella divide, and one blepharo- 

 plast migrates to the posterior end of the cell. The nucleus divides by constriction of 

 the nuclear membrane. There is a prominent parabasal body ("kinetonucleus") which 

 divides by constriction, as does the cell, transversely. 



Belar (1916) described sexual fusions of differentiated individuals of a species 

 parasitic in snails. 



Family 3. Oicomonadacea [Oicomonadaceae] Senn in Engler and Prantl Nat. 

 Pflanzenfam. I Teil, Abt. la: 118 (1900). Family Trypanosomidae Doflein Proto- 

 zoen 55 (1901). Family Trypanosomatidae Grobben 1904. Family Oicomonadidae 

 Hartog. Non-pigmented anteriorly uniflagellate organisms, not markedly amoeboid 

 while in the flagellate condition. 



Oikomonas includes organisms of the character of the family without particular 

 specialization, occurring in contaminated water or soil, and as commensals in the 

 intestine of animals. 



The bulk of the family consists of the slender-celled parasites which may be 

 celled trypanosomes in the broad sense of the word. From the viewpoint of man, these 

 are the most important flagellates, and they have been the most intensely studied. 

 Some are known only from the guts of insects; some occur alternatively in insects 

 and plants; some in insects and vertebrates; and some in vertebrates and in inverte- 

 brates other than insects, as ticks and leeches. The range of parasitization is as 

 though the group had evolved as parasites in insects, and had been carried to 

 other hosts by the activity of insects and other biting or sucking invertebrates. 



Most trypanosomes occur in varied forms. The forms are designated by words 

 which originated as names of genera and remain in use as such. ( 1 ) The leptomonas 

 form has an anterior flagellum but no undulating membrane; it resembles a cell of 

 Oikomonas but is notably slender. (2) The leishmania form has no flagellum; the cell 

 is rounded up and lives attached to, or inside of, cells of the host. (3) In the crithidia 

 form, the base of the flagellum is continued as an undulating membrane more or less 

 to the middle of the cell. (4) In the trypanosoma form, the base of the flagellum is 

 continued as an undulating membrane to the posterior end of the cell. 



The accepted genera are distinguished (artificially, as one may suspect) by stages 

 produced and groups of hosts attacked, as follows: 



l.With leptomonas stages in insects and in 

 Euphorbiaceae, Ascelepiadaceae, and other 

 plants with milky juice Phytomonas. 



1. Confined to invertebrate animals. 



2. Trypanosoma stage known Herpetomonas. 



2. Trypanosoma stage unknown; crithidia 



