238 FAMILY: AMCEBIDzE 



eight small amoebse are formed, and that these conjugate as in E. blattce, 

 but there is as yet no evidence that this occurs. It is unfortunate that 

 Mercier's observations have not been confirmed, and till this has been done 

 some caution must be shown in accepting his account as absolutely 

 correct. 



Genus: Endolimax Kuenen and Swellengrebel, 1917. 



The genus includes parasitic amoebge of small size, each of which has 

 a single nucleus with a relatively large karyosome of irregular shape. 

 The cysts are spherical, ovoid, or more irregular in shape, and possess 

 one, two, four, and more rarely eight nuclei. The genus was created 

 by Kuenen and Swellengrebel for a small amoeba of the human intestine, 

 which was named Entamceba nana by the waiter and O'Connor (1917). 

 Boeck and Stiles (1923) believe that the genus is not sufficiently defined, 

 and that it might be better to suppress it as a synonym of Entamoeba, or 

 to regard it as a sub-genus of Entamoeba. 



ENDOLIMAX OF MAN. 



Endolimax nana (Wenyon and O'Connor, 1917). — Synonymy. — The writer 

 and O'Connor (1917), who first described this amoeba, named it Entamceba nana, while 

 Later in the year Kuenen and Swellengrebel (1917), who also discovered it, employed 

 the name Endolimax iniestinalis. Brug (1917) pointed out that it could not be 

 included in the genus Entamceba, chiefly because of its distinctive nuclear structure. 

 and placed it in the genus V aMkam/pfia. Finally Brug (1918) realized that it did 

 not belong to the genus Valilliampfia, and, accepting Kuenen and Swellengrebel' s 

 generic title, named it Endolimax nana, by which name it is now generally known, 

 though Brumpt (1922) refers to it as Endolimax pJiagocytoides, assuming that an 

 amoeba cultivated from human faeces by Gauducheau (1907. 1998), and named 

 Entamceba jytiagocytoides, was actually E. nana. 



Endolimax ?iana is one of the commonest protozoa of the human 

 intestine. It was seen by the writer in 1912, and by other observers 

 before and after this, but its true nature was not recognized. The writer 

 and O'Connor (1917) found it to be very common in persons in Egypt. 



In the free condition E. nana measures from 6 to 12 microns in 

 diameter (Fig. 111). As usually seen, it moves in a sluggish manner, 

 but it may be quite active when observed on the warm stage. When at 

 rest a superficial layer of clear cytoplasm can be distinguished from a 

 vacuolated endoplasm, but when it performs amoeboid movements little, 

 clear, blunt pseudopodia are formed. The food vacuoles contain bacteria. 

 The nucleus is detected with difficulty in the living organism, so that if 

 the characteristic cysts cannot be found in any specimen of faeces it is 

 often necessary to prepare stained films in order to distinguish the amceba 

 from the small precystic form of E. histolytica. The nucleus is a vesicular 

 structure, and has a diameter of 2 to 3 microns. There is a definite 



