TETRAMITUS MESNILI 57 



Genus. Tetramitus, Perty, 1852. 



Tetramitus mesnili, Wenyon, 1910. 

 Syn. : Macrostoma mesnili, Chilomastix mesnili, Fanapapea intestinalis. 



The genus Tetramitus differs from Trichomonas in possessing an 

 undulating membrane inserted in a deep groove or cytostome. There 

 are three anterior flagella. The pear-shaped organism measures 14 //, 

 by 7 yLt, but smaller examples occur. T. mesnili occurs in the human 

 intestine, having been described by Wenyon 1 (1910) from a man from 

 the Bahamas in the Seamen's Hospital, London. Its occurrence 

 is widespread. Alexeieff considers that Macrostoma and Tetramitus 

 are synonymous. The parasite is the same as Fanapapea intestinalis, 

 Prowazek, 1911, from Samoa. Brumpt (1912) found T. mesnili to be 

 the causal agent of colitis in a Frenchwoman. Nattan-Larrier (1912) 

 considers it of little pathological importance. 



Gabel 2 (1914) described an interesting case of seasonal diarrhoea 

 acquired in Tunis, in which a new Tetramitid was the causal agent. 

 The organism was pear-shaped, without an undulating membrane, 

 and measured 6-5 //, to 8 /JL by 5 //, to 6 p. The cytostome was large, 

 and there was no skeletal support. Encystment occurred. Gabel 

 named the organism Difdmns tunensis and considered that it was 

 pathogenic. 



Genus. Lamblia, R. Blanchard, 1888. 



Syn., Dimorphus, Grassi, 1879, ne c Haller, 1878; Megastoma, Grassi, 1881, nee 

 de Blainville. 



The body is pear-shaped, with a hollow on the under surface anteriorly. It has 

 four pairs of flagella directed backwards, of which three pairs lie on the borders of 

 the hollow disc, and the fourth arises from the pointed posterior extremity. 



Lamblia intestinalis, Lambl, 1859. 



Syn.: Cercomonas intestinalis, Lambl, 1859 (nee 1875); Hexamitus duodenalis, 

 Davaine, 1875; Dimorphus muris, Grassi, 1879; Megastoma entericum, Grassi, 

 1881 ; Megastoma intestinale, R. Blanch., 1886 ; Lamblia duodenalis, Stiles, 1902. 



The organism is pear-shaped and bilaterally symmetrical. It is 

 from 10 p to 21 yit long and 5 //, to 12 //, broad and possesses a thin 

 cuticle. Anteriorly an oblique depression is present, which functions 

 as a sucking disc (fig. 19, s). Its edges are raised above the general 

 surface and are contractile. It corresponds to a peristome and acts as 

 an adhesive organ (fig. 20, b, c). No true cytostome is present. A 

 double longitudinal ridge, representing axostyles, extends from the 

 sucking disc to the tapering posterior extremity, which is prolonged 

 as two flagella from 9 jj, to 14 p long. 



Lamblia intestinalis possesses eight flagella (fig. 19). The first pair 



1 Parasitology , iii, p. 210. * Arch. f. Protistenk., xxxiv, p. I. 



