540 THE AMERICAN NATURALIST. [Vor. XXXIV. 
dant in the brown “ growth,” with which the bottom was 
strewn. With the food thus distributed, the worm-like shape 
was doubtless well adapted to the situation. On the other 
hand, in those dishes containing no sediment or brown “growth,” 
but simply clear water, and in which the Pelomyxas did not 
increase in number, the irregular, branched condition (Figs. 
6 and 7) was extremely common. In these dishes it is evident 
that food was scarce from the start, and the peculiar shape of 
the Pelomyxas is prob- 
ably to be regarded as an 
adaptation to circum- 
stances. We may think 
Fic. 6. Fic. 7. 
Fic. 6. — P. car. as an opaque object. Body thrown into bold curves and complexly branched, 
resting on ‘bottom KM by "A at des gm Remaining pseudopodia project 
freely into water. One millimetre Zeiss A X2. Reduced to % 
Fic. 7. — P. car. as an opaque — Body thrown into two curves, lying in planes e at 
right angles with bes other. Body rests on eei veins d lines) at four points, on 
pseudopodium projecting freely upwards. Zei R 
of the animals as thrusting their substance out in all direc- 
tions of space, searching for food. 
When brought on a slide in a drop of water, these animals 
assume the general shape of Amæba proteus. The body ex 
pands in a horizontal plane, and is, as a whole, applied to the 
surface over which it is creeping (Fig. 8). This is the case 
whether the drop be uncovered or covered — cover was always 
supported with wax feet, so as to permit free movement. This 
flattened shape is not directly caused by confinement between 
two surfaces (surface film and slide, or cover and slide), because 
it is also usually assumed when the Pelomyxa is first placed in 
