308 FAMILY: MONADID^ 



but remained as a small rounded organism with three flagella, one of which 

 sometimes functioned as a trailing fiagellum. Whether this flagellate should 

 be regarded as belonging to the genus Enteromonas depends on whether 

 Fonseca's human Enteromonas was or was not a Chilomastix. Brug (1923) 

 gave a description and figures of E. Jiominis in Sumatra. Some of the 

 figures are suggestive of Tricercomonas intestinalis, and as Jepps (1923) 

 had encountered this flagellate in Malaya, it seemed possible that Brug 

 was actually dealing with it. Brug has kindly allowed the writer to see 

 preparations of his flagellate, which is undoubtedly T. intestinalis. 



The determination of the structure of small flagellates in faeces is an ex- 

 ceedingly difficult procedure. A careful observation of living individuals, or 

 those which have been killed by exposure to osmic vapour or iodine solution, 

 will often yield more information than the study of fixed and stained films. 



D. monadid;e with four flagella. 



A number of coprozoic or intestinal flagellates have been described 

 which possess four anterior flagella and no accessory structures in the 

 cytoplasm beyond the nucleus and blej^haroplasts. These have been 

 placed in various genera, but it is very doubtful if many of these are valid. 

 Their classification is rendered difficult by members of the genus Eutricho- 

 mastix (p. 671), which correspond in structure except for the possession 

 of an axostyle. Other flagellates having a similar structure, but possess- 

 ing a fibre in the place of a true axostyle, belong to the genus Retortamonas 

 (often called Monocercomonas, p. 677). The axostyle or the fibre may 

 not be visible, in which case the flagellates resemble Monadidae with four 

 flagella. It is evident that when an organism is seen with four flagella and 

 no axostyle or fibre, it may be a Eutrichomastix or Retortamonas in which 

 these structures are not visible, or a true Monad with four flagella. 



Genus: Tetramitus Perty, 1852. 

 This genus was created by Perty (1852) for certain free-living, pear- 

 shaped flagellates, which, possess a cytostome and four flagella, one of 

 which might be a trailing flagellum. There are several species recorded 

 by Perty, Klebs, and others. It is possible that some of the flagellates 

 with four flagella which occur in faeces belong to this genus. The form 

 described by Dobell (1908c) as Monocercomonas bufonis from the toad is a 

 pear-shaped organism 12 to 15 microns in length and 3 to 6 microns in 

 breadth. There is no cytostome. The nucleus lies near the blunt end 

 of the body, and in front of it are four blepharoplasts from which arise 

 four flagella, all of 'which are directed forwards. There- was no axostyle 

 or fibre in the body. This flagellate evidently does not belong to the genus 

 Monocercomonas (Retortamonas), as the axial fibre is absent. It may belong 



