690 



definite synonym, and with reference to Stein's (1S78) figures. This 

 species he retained in 1881 as Dicercomonas intestinalis (Dujardin). 



Dimorphus Grassi, 1879 [not Dimorphus Haller, 1878, arachnoid; 

 not Dimorpha Jur., 1807, hymenopteron; Gray, 1840, mollusks; 

 Hodgs., 1841, hirds], with. Dimorphus muris as only, hence type species. 

 This form he eliminated in 1881 as Megastoma eìitericuìn \= Lamblia 

 duodenali^. 



Thus, by the process of elimination, Hexamita Ì7itestÌ7ialis Dujar- 

 din becomes type of Dicercomonas in addition to serving as type for 

 Monomorphus. 



The type-species oi Megastoma, 1881. 

 This genus is based upon Dimorphus muris, hence takes this spe- 

 cies (= Lamblia duodenalis) as type. 



The type-species oi Monocercomonas Grassi, 1879. 



Grassi (1879, p. 446 — 448) proposed the genus Monocercomonas 

 with the subgenera : Monocercomonas, Trichomonas^ Hetortamonas, and 

 Schedoacercomonas , not designating a type and not including in his 

 list of species any previously designated type-species. It is thus clear 

 that the type of Monocercomonas can best be determined by selecting 

 one of the species of the subgenus Monocercomonas. These species are: 



1) Monocercomonas hominis. Gras si's figures in 1881 show that he 



had Tricomonas confusa Stiles [Trichomonas intestinalis Leuckart 

 (name not available]) in mind. 



2) Monocercomonas caviae. Trichomonas caviae Davaine is given as a 



doubtful synonym, but in 1881 Grassi refers to his own obser- 

 vations, together with Trichomonas caviae, under the genus Ci- 

 maenomonas = Tricomonas. 



3) Monocercotnotias coronellae, with Cercomonas colubrorum as a doubt- 



ful synonym. 3f. coronellae and M. hominis are the only original 

 species of Monocercomonas which he retains in this genus in 1881 . 



4) Monocercomonas anatis, to which he refers in 1881 as a Cimaeno- 



monas = Tricomonas. 



5) Monocercomonas batrachorum, with he transferred in 1881 to the 



genus Cimaenomonas , giving Trichomonas batrachorum Perty as 

 definite synonym = Tricomonas. 



6) Monocercomonas muris, to which he refers in 1881 as a Cimaeno- 



monas = Tricomonas. 



7) Monocercomonas lacertae viridis, to which he refers in 1881 as Hete- 



romita lacertae. 



Thus, five species were eliminated by Grassi in 1881, leaving 



