84 
LIFE, IN ITS LOWER FORMS. 
are endowed with the power of spontaneous motion, and 
apparently of choice as to locality, and have a definite 
form, which is commonly pear-shaped, though the outline 
is very flexible and variable. 
As the time of oviposition approaches, the umbrella 
becomes gradually reverted, or turned inside out, the 
ovaries swelling and protruding more and more, until they 
occupy the principal portion of the animal. We believe 
this to be general in the discoid Medusae, having observed 
it in species that belong both to the Covered and Naked- 
eyed divisions — namely, in the genera Chrysaora, Pelagia, 
and Turns. 
In the case of the lovely little Coral-bead Medusa 
( Tunis neglecta ), already alluded to, the phenomena are 
well seen, the ovaries being orange or pale scarlet, studded 
with proportionally large ova, of a rich purple hue. The 
latter appear to escape from the walls of the ovaries, work- 
ing their way out at the sides. They drop down on the 
bottom of the vessel, where they move about slowly for a 
while, but to no great extent, by means of their vibratile 
cilia. By watching them we ascertain the following facts. 
The gemmule, having adhered to some foreign substance, 
grows out into a lengthened form, variously knobbed and 
swollen, and frequently dividing into two branches, the 
whole adhering closely to its support. After a day or 
two’s growth in this manner, a perpendicular stem begins 
to shoot from some point of this creeping root, and soon 
separates into four straight, slender, slightly divergent 
tentacles, which shoot to a considerable length. The whole 
is of a crimson hue, with the exception of the growing 
extremities of the creeping root, which are pellucid white. 
