46 BRITISH FRESHWATER RHIZOPODA. 
In the ooze of ponds; amongst aquatic vegetation ; 
also in marshes and bog-pools; abundant and univer- 
sally distributed. 
Ameba proteus was first described and figured 
by Rosel, under the name Der kleine Proteus, in his 
‘ Insecten-Beliistigung’ (Recreations amongst Insects), 
1755. This was the first introduction to Naturalists 
of the Rhizopoda asa class. Three years later Linneeus 
embodied it in his ‘Systema Nature,’ ed. 10, calling it 
Volvow chaos; Pallas (1766) changed the name to 
Volvox proteus; and subsequently, under a variety of 
designations, each representing, no doubt, some one of 
the many forms assumed by the organism, it figured 
in the works of Continental authors. Ehrenberg, in 
his ‘ Infusionsthierchen’ (1838), described the familiar 
large form as diwwba princeps, a name which it long 
retained; but Leidy, considering that d. princeps 
Ehrenb., and Proteus diffuens Mitller—the original Der 
kleine Proteus of Rosel—represented one and the same 
animal, once more revised the nomenclature and 
adopted the title dAnweba proteus, which is likely to be 
retained. Leidy remarks: “The specific name proteus 
(in Volrow proteus of Pallas) appears the more appro- 
priate, and would at the same time serve to perpetuate 
the name given to the animal by its discoverer.” 
Amwrliu proteus, in one or more of its forms, must 
be familiar to every student of pond-liffe. It is to be 
found in all still ponds which contain healthy vegeta- 
tion, either in the ooze at the bottom, about the older 
stems and leaves of aquatic plants, or in masses of 
floating alge. During active movement the pseudo- 
podia are usually digitate, simple or branched, of 
uniform thickness or tapering to a blunt apex; and 
the nucleus, which is invariably oval, is habitually 
posterior, the contractile vesicle occupying a position 
at no great distance behind it. Necessarily, however, 
during rapid movement, when the animal changes its 
hne of march, forming pseudopodia first on one side, 
then on the other, the nucleus and vesicle get widely 
