182 PARASITIC AMOEBJS OF MAN. 



fined nucleus, but cysts are formed only differing 

 from those of Entamceba coli in the presence of four 

 instead of eight daughter amoebae. The identification 

 of this latter form as Entamceba tetragena explains 

 the apparent contradiction and will, I am sure, render 

 the classification of the amoebae found in man much 

 less difficult. 



GEOGRAPHICAL DISTRIBUTION. The geographical 

 distribution of Entamceba tetragena has not been 

 thoroughly studied. The observations of Viereck 

 and of Hartmann and Prowazek prove that it occurs 

 in East Africa, Farther India, China and probably 

 in other countries of the Far East. My own ob- 

 servations show that it occurs in the Philippine 

 Islands, and it is very probable that it is a frequent 

 cause of dysentery in many of the islands of the 

 Pacific. This species is also found in South America, 

 and it is not unlikely that it may be a frequent cause 

 of dysentery in certain portions of the United States. 



MORPHOLOGY. Entamceba tetragena resembles 

 in certain features of its morphology both coli and 

 Mstolytica. It consists of a mass of protoplasm con- 

 taining a well defined nucleus, is actively motile, and 

 reproduces by simple division and by cysts containing 

 four daughter amoebae. I had an opportunity of 

 studying this organism in f eces from the case already 

 mentioned, and can confirm the description given of 

 it by Viereck and Hartmann and Prowazek. 



