HaAzEN: NEW SPECIES OF LOBOMONAS 133 
more exactly by other recent writers (especially in connection 
with the Polyblepharidaceae) in the sense of euglenoid or amoe- 
boid change of form—and this was the usage of Perty*, by whom 
the word appears to have been coined in 1852—the term is mis- 
leading when applied to Lobomonas: or at least it can be used only 
in a very restricted sense in connection with this genus. The 
young cells of Lobomonas of course do undergo a certain change 
of outline during the formative process within the wall of the 
mother cell: ordinarily essentially the mature form is acquired 
and fixed before their escape, and I have found no evidence that 
it is appreciably altered afterward during activity, though, in 
appearance only, the mature cell may be distinctly reminiscent 
of Amoeba. Nevertheless, this idea of amoeboid change of 
form is most suggestive in a discussion of the formative period 
of such genera as we have under consideration, and for this re- 
stricted period I believe we are entirely justified in drawing a 
parallel with the results of certain recent researches on the 
production of pseudopodia. 
A brief survey of this work may be useful in this connection. 
McClendon (16) has attempted to explain amoeboid movement 
as due to local increase in permeability, the Amoeba simply re- 
ceding from the side on which the permeability has been in- 
creased. Its author himself admits the difficulty of explaining 
positive reactions by this theory, and it certainly does not offer 
any sufficient explanation for the assumption of the character- 
istic cell-form shown by our developing chlamydomonads. The 
closely related hypothesis that production of pseudopodia may 
be accounted for by local variation in surface tension has been 
widely invoked. The re-statement of this theory lately made 
by Thompson (22) may here be passed over, even as this stim- 
ulating writer has all but ignored the evidence which has been 
accumulating against the surface tension explanation. Both 
the permeability idea and the surface tension explanation as 
ordinarily employed are objectionable, in that they depend too 
tabolie. Hirunter verstehe ich die durch innere Vorgdénge bedingte 
wechselnde Gestaltanderung. Seit langem bei den Amiben bekannt ist sie 
bei den Infusorien so viel als nicht beachtet worden. [Perty: Zur Kenntniss 
kleinster Lebensformen, p. 127. Berne. 1852. 
Since this term Metabolie seems to be unfamiliar to American botanists 
because of its very restricted usage, and since it has even been r endered as 
equivalent to metabolism in a recent inane dictionary for chemists, 
it appears to be worth while to call is original definition. 
