245 
By the side of these sharply circumscribed and entirely 
motionless globular forms are to be observed certain cytods 
quite similar to those just described, excepting that they carry 
either one or more often two prolongations in the form of 
arms, which I should call pseudopodia, if they did not exhibit 
entirely peculiar characteristics which separate them very 
obviously from the pseudopodia of the Monera, the Forami- 
nifera, and the Radiolaria. I should be more inclined to 
compare them to the mobile appendage of the Noctiluce, 
chiefly on account of the constancy of their form and of the 
nature of their movements. These cytods with prolonga- 
‘tions I shall call generating cytods. 
Firstly, as to the characters which were presented by the 
prolongations of the cytod which I have represented in 
figs. 6, 6”, 6”. The prolongations to the number of two 
are inserted at a little distance one from another on the same 
hemisphere. They are not only of unequal length, but they 
differ notably from one another in all their characters. ‘That 
which is the shorter is at the same time the thinner, more 
delicate, with paler outline, and almost completely devoid of 
mobility. If in a displacement which the corpuscle under- 
goes either in virtue of its own vitality, or in consequence of 
a current which carries it along—this arm comes in contact 
with a resisting body, it becomes reflected, bent back, and I 
have seen this bend, produced accidentally, persist during 
more than three quarters of an hour. ‘The protoplasm which 
constitutes this arm is pale but slightly refringent, very 
finely granular, and almost devoid of granules of appreciable 
dimension. I consider these last granules as being nutritive, 
combustible elements; and the almost complete absence of 
mobility in this arm may be explained by this fact that the 
combustion—that is to say, the liberation of the force neces- 
sary for mechanical movement—does not operate except with 
extreme slowness in this inert arm. 
The other arm is notably longer, and also a little broader ; 
its contours are darker, and the protoplasm which compose 
them is more refringent. Besides the almost imperceptible 
molecules which distinguish the protoplasmic matter, in this 
arm opaque granules are remarked. ‘These granules are 
chiefly abundant at the slightly enlarged and very mobile 
extremity of this arm. It is thus very granular, and this 
character is sufficient to enable one to distinguish, at first 
sight, the second arm from its neighbour. It differs further 
from the first-mentioned prolongation by its extreme mobility. 
Two modes of manifestation of this mobility are distinguish- 
able. Firstly, the arm can vibrate, very much as does the 
