ECOLOGY, COMMENSALISM AND PARASITISM 387 



in the encysted ameba followed by division of the body into 

 binucleated spores which repeat the cycle upon ingestion by Daphnia. 

 This history is so unusual for amebae that Chatton placed it in 

 a new family, the Sporoamoebidae. 



Vertebrates, particularly mammals, have been more extensively 

 studied for parasitic amebae than have invertebrate animals. 

 Amoeba froschi was found by Hartmann (1907) in frogs' feces, and 

 Valkampfia (Epstein and Lovasky, 1914) from the frog intestine, 

 and A. laeertae, Hartmann, and A. dobelli, Hartmann, from the 

 intestinal contents of lizards. Other species described from reptiles 

 are: Endamoeba testudinis, Hartmann, in the land turtle Testudo 

 graeca; E. barreti, Hegner and Taliaferro, in Chelydon serpentina; 

 E. serpent is, Da Cunha and Fonseca (1917), in the snake Drimobius 

 bijossatus; E. varani, Lavier (1923), from Varanus viloticus. Few 

 amebae have been reported from fish. The genus Proctamoeba 

 salpae, named by AlexeiefT (1911) for an intestinal ameba discov- 

 ered by Leger and Duboscq (1904) in the marine fish Box boops, 

 is undoubtedly an Endameba, so Proctameba is a synonym. 



Few parasitic amebae have been reported from birds. Fantham 

 (1912) described E. lagopodis from the intestine of the grouse, and 

 E. anatis from South African ducks (1924), and Tyzzer (1920) found 

 E. gallinarum, Tyzzer, in chickens and turkeys. 



Amebae resembling the type of E. dysenteriae and E. colt 

 have been described from mammals of different kinds. Apart 

 from human intestinal forms they have been reported from the 

 mouse: E. muris, Grassi (1879), and E. decumani, Kessel (1924); 

 from the rat: E. ratti; from rabbits: E. cuniculi, Brug (1918); 

 from guinea-pigs: E. cobayae, Walker (1908) (E. caviae, Chatton, 

 1918); from swine: E. debliecki, Nieschultz (1925), E. polecki, 

 Prowazek (1912) (E. suis, Hartmann, 1913); from sheep: E. ovis, 

 Swt'llengrebel (1914), E. caprae, Fantham (1923); from cattle: E. 

 bovis, Liebetanz (1915); from horses: E. intestinalis, Fantham 

 (1920), and E. equi, Fantham (1921). In addition to these, suc- 

 cessful inoculations of human dysenteric amebae have been made, 

 particularly in cats and monkeys. 



Parasitic amebae in man, naturally, have attracted most atten- 

 tion and have been extensively studied. Tropical dysentery is 

 such a dreaded malady that students over the entire world have 

 contributed until today there are few important gaps in the patho- 

 logical history of the disease or in our knowledge of the causative 

 agent. 



Amebic dysentery has had a long and confusing history in which 

 taxonomic synonyms and etiological misfits have played a con- 

 spicuous part. The final chapter has not yet been written, but 

 much of the earlier confusion has been cleared and students of the 

 subject are working with a common understanding. In my opinion 



