MOVEMEXTS IX THE ORGAXS OE PLAXTS 3 
snail-like or creeping motion. “ Red snow,” the sudden appear- 
ance of which in the mountainous districts of Europe and 
Asia was believed to foretell disaster, the microscope reveals to 
be really of simple algal origin. It first appears as a simple 
spheroid, which soon by division and fission produces other 
similar cells at its sides. These soon become detached, and 
as soon as the daughter-cell so produced is free, it displays at 
the narrow extremity two rotating cilia, by means of which it 
moves about in the snow-water with considerable velocity. How 
long this motile stage lasts has not been determined. 
The singular confervoid alga Oscillatoria, which derives its 
generic name from its attractive movements when floating in 
water, has from a very early period engaged the attention of 
students of minute forms of plant life, and Loudon remarks 
that the oscillation of the filaments seems almost of an animal 
nature, though it is found to be frequently purely mechanical, 
arising simply from the elasticity of the filament. Professor 
Agardh declares, however, that Oscillatoria curviceps has actually 
the motion of an animal, namely, of a creeping not oscillating 
nature. Anton Kerner says they stretch themselves and then 
contract again, coil up and then straighten out like snakes, and 
— most characteristic of all — make periodic oscillations in the 
water. Modern belief is that infinitesimally fine filaments of 
protoplasm penetrate the cell-wall and act like propellers in a 
ship and so cause the motion. 
The entrancingly interesting microscopic plant Volvox globator 
is a globe of living jelly, which moves about in the water with 
a regular motion, propelled by synchronous strokes, like a galley 
manned by several oarsmen, as soon as the crew of this fairy 
vessel begin to manipulate their propellers. The effect is 
exceedingly graceful and has justly filled observers of all periods 
with astonishment. No one, indeed, seeing a Volvox sphere 
rolling along can fail to be impressed and delighted. The very 
remarkable “ fructification ” that takes place in Cham vulgaris was 
first noticed by Mr. Varley in 1833. He says the ripe ‘‘globule ” 
(now known to be an antheridium) spontaneously opens, the 
filaments expand and separate into clusters ; these tube-like 
filaments are divided into numerous compartments in which are 
produced the most extraordinary objects ever observed of 
vegetable origin. At first they seem agitated and moving in 
their cells, wfiere they are coiled up in their confined spaces, 
every cell holding one. Then they gradually escape from their 
cells, and the whole field of the microscope soon appears filled with 
life. They are generally spirals of two or three coils, and never 
become straight, though their agitated motion alters their shape 
in some degree ; . . . they swim about freely for a time, 
but gradually getting slower and slower, in about an hour become 
quite motionless. These moving antherozoids have also been 
observed in Sphagnum (Bog-moss), and by Unger were classed as 
infusoria. Somewhat similar are the movements of the spores 
