242 University of California Publications in Zoolo(jy [Vol. 16 



A. INTRODUCTION 

 I. HTSTOBICAL 



Since amoebas may be obtained easily, cultured without difficulty 

 in the case of many species, and experimented upon readily owing to 

 their size and numbers, they have been the objects of extensive obser- 

 vation and investigation. Most of the early work was necessarily 

 observational on the living vegetative stages. According to Dujardin 

 (1841), an amoeba was first seen by Rosel (1746-1761), then cited by 

 Linnaeus (1758) and Pallas (1766) under the name of Volvox chaos, 

 Chaos proteus, and Volvox proteus. Miiller (1786) later saw what he 

 named Proteus diffluens. Many others are recorded from this time on. 

 Gleichen (1778) found a small form in some infusions. Bory (1826) 

 created the genus Amiba, the spelling of which was changed to Amoeba 

 later bj' Ehrenberg (1839), in which he put three true amoebas and 

 some other forms entirely diiferent. In his enthusiasm, Losana de Turin 

 (1827) described no less than sixty-nine species which were for the 

 most part modifications of the form of A. diffluens. Dujardin (1841) 

 described the first limax. He found it in some water from the Seine 

 and named it Amoeba Umax. Its size he gave as 0.10 mm. by 0.03 mm. 

 He characterizes it as "Diaphone arroudie aux deux bouts, tres peu 

 lobee ; contenant des granules tres distincts et une vacuole tres pro- 

 noncee. " There were numerous other species described after this 

 date, but they were characterized principally by pseudopodia and size. 

 The most complete and critical attempt to systematize our knowledge 

 of these organi.sms is that of Penard (1902). The first cy.st, probably, 

 was described by Auerbach (1856) in A. bilimbosa. Later Wallich 

 (1863) described one and says that Schneider had done so before 

 he did. 



The binary fission of amoebas was described in the early work as 

 amitotic. Schulze (1874) from his observation on A. polypodia came 

 to this conclusion and his figures of this are found in many textbooks 

 of zoology. With the advent of the staining method it was found that 

 division took place mitoticall.y. Then arose discussions as to whether 

 or not amitosis was degenerate and mitosis the normal process. Gruber 

 (1894) held that mitosis was normal. 



Promitosis was first described in limax amoebas by Vablkampf 

 (1904), then by Nagler (1909) who gave it the name. Both of these 



