1905 | NoTEs ON FRESH-WATER RHIZOPODS. 17 
at the end of half an hour as to be hardly like the original. This 
movement is peculiar. At any part of the body the ectosare is 
pushed out in the form of small finger-like processes called pseudo- 
pods: these increase in size, still consisting of ectosarc only; gran- 
ules from the endosarc stream into it, and the projection comes to 
have the same construction as the rest of the Amoeba: every pseu- 
dopod protruded from one part of the body necessitates the with- 
drawal of an equal volume from some other part. The peculiar 
movements of Amoeba may be imitated by taking a lump of dough 
or putty and sqneezing it between the fingers; as it is compressed 
in one direction it will elongate in another; regulating the pressure 
so as to cause the protrusion of narrow portions when the resem- 
blance to the movement described, will be fairly close, but with 
this radical difference—the one is acted on, the other acts for itself. 
In the granular mass are darker spots which do not change their 
form while the protoplasm is flowing all around them. These are 
called ‘‘ nuclei.”’ ‘‘ They are usually large, spherical, hyaline cor- 
puscles, in most cases situated back of the middle of the animal ”’ 
and are essential to life and reproduction, ‘‘In the clear space sur- 
rounding the granular matter is a space which widens slowly and 
then rapidly contracts. This is called the contractile vesicle, and 
probably serves for respiration by taking water laden with oxygen 
into the body; and for excretion, by forcing water laden with waste 
products out of the body; ” but its true nature is not fully under- 
stood. Not only do Rhizopods move by means of pseudopods, 
but they capture food with them as well. This food consists of 
diatoms, desmids and other alge, rotifers—in fact anything they 
can hold. Within the body the food is usually seen as small spher- 
ical masses, green, brownish or red. In capturing food the jelly 
mass spreads itself over the organism so as to envelop it, (pro- 
toplasm can unite with itself whenever the parts come into contact) 
closing over it thus bringing it into its midst. The digestible por- 
tions of the prey are extracted, digested, and then the insoluble 
parts are gradually squeezed to some part of the exterior and gra- 
dually forced out. This is the earliest condition in which the pro 
gress of digestion can be recognized. 
The process of reproduction is by division, and is very simple. 
The nucleus first divides into two: the whole organism elongates, 
