490 
POPULAR SCIENCE REVIEW. 
of its ungrateful guest, for, though half of its young embryos 
may be devoured, it glides along with as swift and as majestic 
a course as ever ; nor are the vibrations of its cilia intermitted, 
for any floating atoms that he in its track are hurled away 
with impetuosity the moment they come within reach of this 
living whirlpool. 
In some spheres we find eggs with Notommatce ; in some, eggs 
alone. Perhaps the parasite is always hatched in a parent 
Volvox, but the embryo globe is probably entered from without, 
and the Notommata is then expelled with it. The Notommatce 
frequently eat them way out, and swum at freedom. Observing 
one, large with a nearly matured egg, in the globe of a small 
Volvox, I opened the latter with a fine needle, and freed the 
Notommata. This I placed in clear water, and added several 
Volvoees of various ages, taking care that none contained a 
parasite. I then watched its proceedings, to see if it would 
enter any one of the globes, but though in the course of its 
swift and headlong rotation it now and then came into contact 
with a globe, and would arrest its career to play over its 
surface, and even to nibble at it, it would presently dart away 
again, not entering one in the lapse of several hours. In the 
course of this time it deposited its egg loose in the water, which 
probably it would not have done had I left it to follow the 
dictates of its instinct. 
For further details of the economy of this interesting crea- 
ture I must refer to a paper of my own in the Transactions of 
the Microscopical Society of London for 1851. 
EXPLANATION OF THE ILLUSTRATIONS. 
Plate XIX. — Fig. a represents Eosphora aurita, seen from the back, the ear- 
like lobes evolved, in the act of swimming. 
„ Fig. b represents the same animal, seen from the side, in the 
position assumed in marching and feeding. Both figures 
are magnified about 250 diameters. From the life. 
