225 
VOLVOX GrLOBATOK. 
By ALFRED W. BENNETT, M.A., B.Sc., F.L.S. 
LECTURER ON - BOTANY AT ST. THOMAS’S HOSPITAL. 
[PLATE Y.] 
T HE organism which we are about to describe has long been 
a favourite object for observation to microscopists, not only 
from the extraordinary beauty and delicacy of its structure, but 
from the remarkable phenomenon which it presents of a member 
of the vegetable kingdom endowed with a power of motion 
apparently as spontaneous as that possessed by any organisms 
belonging to the animal kingdom. The very location of the 
Volvox among plants has indeed been challenged. Like many 
others which are now placed, by almost universal consent, 
among the lower classes of Cryptogams, it was held by the dis- 
tinguished naturalist Ebrenberg to be of animal nature. If, 
however, any doubt remained as to its true vegetable character, 
this has been completely set at rest by the researches of Professor 
Cohn,* who has only quite recently for the first time followed 
out completely the various stages of reproduction of this singular 
organism. In no English work will they at present be found 
adequately described, although so many observers had before his 
time had it under their notice. 
The Volvox globator is not uncommon in clear pools on 
commons, and in similar situations, and is visible to the naked 
eye as a minute pale-green globule rolling through the water, 
passing rapidly across the field of view under the microscope, 
its full diameter being perhaps -gL of an inch. Under the 
microscope it is seen that the rotatory motion is caused by innu- 
merable fine transparent vibratile cilia, with which the surface 
is studded. The appearance presented by the entire body is that 
of a globular transparent, hollow, membranous sac, through which 
these cilia protrude, and studded with bright green points, while 
in the interior are seen a small number of dense green globes. 
In the autumn or early winter these internal globes have often 
* “ Beitrage zur Biologie der Pflanzen,” Yol. i. Heft 3, 1875. 
NEW SERIES, VOL. II. — NO. VII. Q 
