CLASSIFICATION AND NOMENCLATURE. 29 



classification may be said to be final, but other species 

 have been described and classified which are still in 

 doubt and in which the present classification may or 

 may not be correct. 



The Amcebina are divided by zoologists into the 

 Reticulosa, having filamentous pseudopodia ; and the 

 Lobosa, having lobose pseudopodia; the latter are 

 divided into the Gymnamceba, in which the proto- 

 plasm is naked; and the Testacea, in which the 

 protoplasm is surrounded by a shell. 



The parasitic amoeba? of man belong to the 

 Gymnamceba, or naked amoebae having lobose pseudo- 

 podia, and are placed in the genus Entamoeba created 

 by Casagrandi and Barbagallo. All free-living forms 

 are placed in the genus Amoeba and are differentiated 

 from the members of the genus Entamoeba by the 

 presence of a contractile vacuole and other morpholog- 

 ical characteristics, and their inability to exist as 

 parasites within man. 



In addition to the two genera mentioned, we 

 must include the genus Paramceba, which contains a 

 marine amoeba, Paramceba eilhardi, and the parasitic 

 form known as Paramceba hominis. 



The absence of amoebae in numerous typical cases 

 of dysentery, and their presence in health and dis- 

 eases other than dysentery, has gradually led to the 

 grouping of students of the subject into three schools, 



