34 FRESH-WATER RHIZOPODS OF NORTH AMERICA. 



contents yellowish, and the exterior investment colorless, just as our large 

 common Amoeba appears under partially reflected and transmitted light. 



Most of Rosel's figures exhibit the characteristic changes of form of 

 the Proteus, and these certainly agree with those of our common large 

 Amoeba, and better with those of Ehrenberg's figures of Amoeba princeps 

 than with those of the same author's figures of Amoeba diffluens. Of the 

 figures of Rosel, one he likens in its branching to the antler of a deer, a 

 resemblance which all must have seen who are familiar with the large 

 Amoeba commonly regarded as the Amoeba princeps. 



As regards both size and color of the Proteus of Rosel, it might refer 

 to other large Amcebag than A. princeps, as for instance the A. villosa of 

 Wallich, or the Pelomyxa palustris of Greeff ; but the changes of form and 

 the extension and shape of the pseudopods rather approximate it to the 

 former. 



Midler's description and figures of Proteus diffluens, which that author 

 regarded to be the same as Rosel's Proteus, appear to apply to the same 

 animal as Ehrenberg's Amoeba princeps, rather than to the Amoeba diffluens 

 of the latter. 



From the review thus presented, I think it will be admitted that the 

 little Proteus of Rosel, the Proteus diffluens of Midler, the Amoeba princeps 

 of Ehrenberg, and our large familiar Amoeba, are to be regarded as one 

 and the same animal. 



It has been suggested that all forms of Amoeba may eventually be 

 found to be transitory phases of the same species ; but even this view does 

 not render the determinations of Ehrenberg and those who follow him in 

 relation to Amoeba princeps and Amoeba diffluens any the less incorrect. 



Having arrived at the conclusion that our common large Amoeba, 

 usually called Amoeba princeps, is the same as Rosel's Proteus, the question 

 arises as to its appropriate name. 



Ehrenberg changed the name of Amiba of Bory into Amoeba ; and 

 had it not been that the latter mode of spelling the word had come into 

 such common use, I would have dropped the ugly diphthong, and resumed 

 the word Amiba, as employed by Bory arid Dujardm. 



Of the specific names employed for the little Proteus, that of chaos in 

 Volvox Chaos of Linnpeus is oldest ; but that of proteus in Volvox Proteus of 

 Pallas appears more appropriate, and would at the same time serve to 



