Some Observations on Amoeba proteus. 205 
probability in his calculation that he brings the size of his specimen near 
to that of Ehrenberg’s A. princeps. 
In 1863 H. J. Carter! and Wallich? differed strongly over the amceba 
each had independently observed—the villous tuft being the chief cause 
of the dissention. From Carter’s own description he certainly observed 
A. princeps, also the multinucleate form of A. proteus, and an infected 
specimen. 
The amceba named A. villosa by Wallich feeds voraciously on diatoms 
and the villous tuft is not a constant feature, a fact recorded by Waliich 
himself, who thought the real difference between A. princeps and A. villosa 
might lie in the nucleus; which difference again might only be a phase in 
the life-history. | 
Leidy first groups these amcebe under the name of Ameba chaos, but 
finally decides on A. proteus in his survey of 1879, placing A. villosa apart. 
The illustrations in this publication are the best produced, but no distinction 
of types is made, although peculiarities are recorded, with the obvious result 
that later workers think to make their description beyond reproach, by 
stating that the amceba they studied was A. proteus as figured by Leidy— 
but which ? 
Griiber*® broke away from this tentative grouping of Leidy’s in 1884, but 
he retains the name A. protews for one of the amcebe, and the amceba 
chosen by him to perpetuate that name is the type I have here named 
provisionally A. proteus X, that is A. proteus Pallas, but in his figure the 
crystals are not well drawn. 
Later Griiber calls into question Butschli’s description of the nucleus of 
A. proteus, and concludes that if Butschli’s description is accurate “then in 
one and the same species an entirely different arrangement of the chromatin 
in the nucleus is possible,” and one would add very probable. 
The well-known paper by Scheel* (1899) on the cyst of A. proteus 
contains no description of the free amceba either in the text or in the 
illustrations. 
In 1902 Penard’s work on the “Faune Rhizopodique du Bassin du 
Leman”? appeared with excellent text descriptions and figures, though 
small, of each amceba met with. In his classification he also breaks up 
the A. proteus group, giving yet another set of specific names—thus 
1H. J. Carter, Annals and Mag. Nat. Hist., vol. xii., 1863. 
2 Wallich, Lbid., vol. xi., 1863. 
? A. Gruber, Zeitschrift fiir wiss. Zool., Bd. xli., 1885. 
4 Scheel, Festschrift f. Kupffer, 1899. 
° Penard, Faune Rhizopodique du Bassin du Leman, 1902. 
