Phylum Protoplasta [165 



In making the clearly natural group of trichomonads a separate order, Kirby ( 1947 ) 

 removed the majority of the species formerly assigned to this order, and left a mis- 

 cellany of small isolated families. It seems not expedient to make them several small 

 orders, as Grasse has done; rather they are to be held together until their respective 

 relationships become evident. A hint of Hall has led in the present work to the trans- 

 fer of family Trimastigida to order Ochromonadalea. 

 1. With a single nucleus and neuromotor system. 

 2. Cells not spirally twisted, at least not as 



wholes and not conspicuously Family 1. TEXRAMiTroA. 



2. Entire cells conspicuously spirally 

 twisted. 



3. With four free flagella Family 2. Streblomastigida. 



3. With four or eight flagella whose 

 proximal ends are grown fast to the 



cell membrane Family 3. Dinenymphida. 



1. With one or several nuclei and two or more 



neuromotor systems Family 4. Oxymonadida. 



1. With two nuclei and neuromotor systems Family 5. Trepomonadida. 



Family 1. Tetramitida [Tetramitidae] Kent Man. Inf. 1: 312 (1880). Families 

 Tetramitina and Polymastigina Biitschli in Bronn Kl. u. Ord. Thierreichs 1: 841, 

 842 (1884). Family Tetramitaceae Senn in Engler and Prantl Nat. Pflanzenfam. I 

 Teil, Abt. la: 143 ( 1900) . Family Polymastigidae Doflein Protozoen 83 ( 1901 ) . Fam- 

 ily Chilomastigidae Wenyon (1926). Family Costiidae Kudo Handb. Prot. 153 

 (1931). Family Retortomonadidae Wenrich 1932. Cells mostly dorsiventral and 

 with four flagella; these uniform or differentiated; when differentiated, one or two 

 may trail behind the cell. Axostyles present or absent, parabasal bodies not reported. 

 Like the order, the family is a miscellany; good authority has made as many as four 

 families of the few genera. Tetramitus, free-living, unfamiliar. Costia, occurring 

 usually as sessile parasites on fishes. Polymastix, in insects. Monocercomonoides, in 

 insects and vertebrates. Chilomastix, in insects and vertebrates, cells marked by a 

 cytostomal groove into which one of the flagella, shorter than the others, is recurved. 

 The species which occurs in man (usually, as it appears, as a harmless commensal) 

 is in most works called C. Mesnili; the correct name is apparently Chilomastix Hom- 

 inis (Davaine) n. combl. Current authority places next to Chilomonas the biflagellate 

 Retortomonas, also in insects and vertebrates, and having cells of essentially the 

 same structure. 



^Kofoid (1920) gave the history involved in this combination. Davaine, 1860, de- 

 scribed the flagellates Cercomonas Hominis var. A and var. B. The two forms are 

 not of the same species, and Moquin-Tandon, in the same year, re-named them 

 respectively C. Davainei and C. obliqua. They are not of the same genus, being re- 

 spectively a Chilomastix and a Pentatrichomonas, under which genera they have 

 various names. Kofoid named them respectively Chilomastix davainei and Tricho- 

 monas hominis. In so doing, he may be held to have exercised his right to choose a 

 type in a group in which no type has been designated; but it is arguable on the con- 

 trary that an author who designates a var. A designates the type in doing so. It is 

 on the basis of this argument that the new combination here published is applied 

 to the Cercomonas Hominis var. A of Davaine. 



