CLASSIFICATION AND NOMENCLATURE. 37 



more and more convinced that species differentiation 

 should rest chiefly upon differences in the life cycle 

 rather than upon mere morphological variations, and 

 the writer believes that a species should not be de- 

 scribed until at least the larger portion of its life 

 cycle has been demonstrated. 



The species which are still of uncertain value are 

 the following: 



Genus, Entamoeba. 



Species, Entamoeba undulans, Castellani, 1905. 



Amoeba pulmonalis, Artault, 1900. 



Amoeba urogewtalis, Baelz, 1903. 



Amoeba miurai, Ijima, 1898. 



Amoeba gingivalis, Gros, 1848. 



Amoeba dentalis, Grassi, 1879. 



