PELOMYXA PALUSTRIS. 79 
large solid or rigid body,” when the contour becomes 
temporarily quite ragged, and whip-like pseudopodia 
of exceeding fineness are shot out with great sudden- 
ness and velocity, extending to a considerable length. 
“ Pseudopodia of this kind,” the author remarks, “are 
exceedingly attenuated and acute, and are, for a great 
part of their length from the tip inwards, perfectly 
hyaline, appearing to be actual prolongations of the 
hyaline border ; they often, but by no means always, 
radiate outwards, and very frequently anastomose, the 
connecting bridge between two pseudopodia being 
sometimes hyaline, but more often consisting of fine 
strands of granular protoplasm.”* 
As bearing on the subject of classification, we are 
unable as yet to see that the production of these fine 
and occasionally anastomosing pseudopodia are of any 
special significance. They are evidently adventitious, 
depending upon conditions peculiar to the individual, 
and not characteristic of the species in the absence of 
such conditions. It does not appear that they perform 
any natural function. They are projected “ with great 
suddenness and velocity,” when some hard substance 
is being got rid of, and so soon as the producing cause 
is withdrawn, they are re-absorbed. In other words, 
their production is the result of a sudden rupture of 
the ectosare, occasioned by the accidental circumstance 
of a foreign body having to be ejected at that spot. 
This removes them from the category of true pseudo- 
podia, and marks an essential difference between them 
and the finely-attenuated and anastomosing pseudo- 
podia which distinguish the Reticulosa. 
2. Pelomyxa villosa Leidy. 
(Plate VII, figs. 4-6.) 
Ameba villosa (Wallich) Stack in Intell. Obs. III (1863), 
p. 430, ff. p. 433. 
Ameeba sabulosa Lztpy in Proc, Acad. Nat. Sci. Phil. 1874, 
p. 87. 
* Loc. cit., p. 390. 
