538 THE AMERICAN NATURALIST. [VoL. XXXIV. 
clear water without any of the brown stuff or sediment, and the 
Pelomyxas were changed to fresh water occasionally. No 
Cyclops or other Crustacea developed in these dishes, For a 
time Stentor cwruleus was supplied, and later a small brown 
Stentor, Paramcecium, and other Infusoria. The Pelomyxas 
remained active and kept their size during this period, though 
they did not materially alter in number. After a few days 
they were no longer fed, though the dishes were kept supplied 
with fresh water. They gradually decreased in number, dimin- 
ished very noticeably in size, and were very sluggish in their 
movements. The last of these individuals were made use of in 
early November. These starved individuals were about one- 
third the size of those originally put in the dish. It is possible 
of course that some division went on during this period of star- 
vation, and that the shrinkage in size was not due age to 
the loss of tissue. 
To this form I have given the name of P. carolinensis. Its 
points of difference from the related species of Pelomyxa will 
be discussed later. 
Description of Pelomyxa carolinensis. 
Habitus. —The body, when viewed by reflected light, is 
white and conspicuous. When left for some time undisturbed 
(in small aquarium dishes suitable for microscopic observations), 
the body assumes a great variety of shapes, many of them indi- 
cating a high degree of consistency in the superficial layer of 
protoplasm. Owing to the large size of the species, these 
shapes may, with some success, be made out even with the 
unaided eye, though better with the help of a simple lens and 
low objective. 
The body is very apt to assume an elongated, more or less 
rod-like shape, as in Fig. 1; sometimes enlarged at one end 
(clavate), as in Fig. 2. The elongated body may lie flat on the 
supporting surface, as in Figs. 1 and2. More frequently the 
body is thrown into one or more curves, the animal resting on 
the bottom by its two ends, as in Figs. 3 and 4. Occasionally 
a Pelomyxa was observed in the remarkable attitude shown in 
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