DIENTAMOEBA FRAGILIS n. g., n. sp., A NEW 
INTESTINAL AMOEBA FROM MAN. 
By MAEGARET W. JEPPS, 
Ballmrst Student, Newnhani College, Cauibridge, 
AND CLIFFORD DOBELL, 
Imperial College of Science. 
(A REPORT TO THE MEDICAL RESEARCH COMMITTEE\) 
(With Plate VII.) 
CONTENTS. 
PAGE 
Introduction ........... 352 
Description of the Amoeba ........ 353 
Di.seussion of the nuclear system of Dientamoeba. Nomenclature . 360 
Diagnosis of Dientamoeba fragilis ....... 363 
Notes on infected cases . . . . . . . . . 364 
References ........... 366 
Description of Plate ......... 367 
INTRODUCTION. 
It is now becoming generally recognized that there are three different 
amoebae which may be present in the human bowel—the harmless 
Entamoeba coli (Losch) Schaudinn and “Entamoeba’’ nana Wenyon and 
O’Connor, and the pathogenic E. histolytica Schaudinn. We have dis¬ 
cussed these three species in an earlier paper (1917), and there noted 
their chief distinctive characters. In the present paper we shall describe 
a fourth and much less common species which we have recently en¬ 
countered. It differs in some respects so conspicuously from the others 
that it appears to us necessary to place it not only in a new species, 
but even in a new genus. We propose therefore the new name Dientamoeba 
^ The observations here described were chiefly made by us whilst working at the 
Wellcome Bureau of Scientific Research, and with the aid of grants from the Medical 
Research Committee. We take this opportunity of recording our indebtedness to the 
Bureau for the facilities and assistance which it has afforded us in the course of our work. 
