234 



FAMILY: AMCEBID^ 



four-nucleated cysts with chromatoid bodies are produced. It clearly 

 belongs to the genus Entamoeba. 



Amoebae belonging to this genus occur also in invertebrates. Noller 

 (19r2a) discovered a form resembling E. histolytica in the vagina of the 

 horse leech. The free forms varied from 4 to 35 microns in diameter, and 

 the cysts, which measure 7 to 11 microns, had four nuclei and chromatoid 

 bodies. Noller gave the name of E. aulastomi to this amoeba, which has 

 been cultivated by Drbohlav (1925e). Another invertebrate form is 

 E. minchini, described from the larvae of Tipulids by Mackinnon (1914). 

 The free amoebae were 5 to 30 microns in diameter, while the encysted 



forms contained 



a 



maximum of ten 

 nuclei (Fig. 108). 



Keilin (1917) de- 

 scribed as E. mesnili 

 an amoeba which lives 

 jjl' in the intestine of the 

 larvae of the Diptera 

 Tiichocera hiemalis 

 and T. annulata. The 

 amoebae vary inlength 

 from 6 to 24 microns, 

 and in breadth from 

 4 to 8 microns (Fig. 

 109). There is a clear 

 ectoplasm and a finely 

 granular endoplasm 

 which is free from 

 food vacuoles. A 

 curious feature of the 



Fig. 109. — Entamceba mesnili from the Intestine of 

 Larv.e of Trichocera hiemalis and T. annulata 

 (x 2,000). (After Keilin, 1917.) 



1. Uninucleated form. 



2. Multinucleatsd form with trailing p.5eiulopodium. to whicl 



are adherent bacteria and other debris. 

 .3. Multinucleated form in division. 

 4. Encysted form with three nuclei. 



amoeba is that many forms are multinucleate and contain from four 

 to fourteen nuclei according to their size. These multinucleate amoebae 

 divide to give rise to daughter forms, which are also multinucleate. 

 Sometimes uninucleate forms are budded off, and these apparently 

 increase in size and become multinucleate. Encysted forms measuring 

 8 to 11 microns in diameter are found. They have two to four nuclei. 

 The nucleus of this amoeba contains a large central karyosome, and in 

 this respect differs from the typical nucleus of Entamoeha, so that it is 

 possible that the amoeba belongs to another genus. 



Brug (1922) describes as E. helostomce a large amoeba from the intestine 

 of the water bug Belostoyna sp. of Java. The amoeba was said to be of 

 the E. histolytica type. Cysts, however, were not seen. 



