MEDUSIDE. 169 
peduncle or base of the brown body up to the head. I have round 
that each of these small brown bodies presents a very distinct red 
point placed on the dorsal face of the yellow head ; and when I 
compare this with my other observations of similar red points in 
other animals, I find that they greatly resemble the eyes of the Rotifera 
and Entomostraca. The bifurcating body placed at the base of the 
brown spot appears to be a nervous ganglion, and its branches may 
be regarded as optic nerves. Each pedunculated eye presents upon 
its lower face a small yellow sac, in which are found, in greater or 
smaller numbers, small crystalline bodies clear as water.” The 
presence of a red pigment in very fine grains is an argument in favour 
of the existence of visual organs in these creatures, for the small 
crystals disseminated in the interior of the organ would no doubt 
perform the part of refracting light which is produced by the 
crystalline lens in the eyes of vertebrated animals. Moreover, it is 
found that there are marginal corpuscles analogous to these brown 
spots in other species of Meduse. They are of a palish yellow, or 
quite colourless, and enclose sometimes a single, sometimes many 
calcareous corpuscles. When they are colourless, some naturalists 
have rather taken them for organs of hearing reduced to their most 
simple expression. 
The Medusze are not, according to Agassiz, absolutely destitute 
of nervous system. We have seen that they may have ganglions, 
and probably optic nerves. Ehrenberg also states that these have 
ganglions at their base, which furnish them with nervous filaments. 
Without entering further into the details of their delicate and 
complicated structure, we shall pause briefly on their mode of repro- 
duction. We shall find here physiological phenomena so remarkable 
as to appear incredible, had not the researches of modern naturalists 
placed the facts beyond all doubt. “Which of us,” says M. de 
Quatrefages, “would not proclaim the prodigy, if he saw a reptile 
issue from an egg laid in his court-yard, which afterwards gave birth 
to an indefinite number of fishes and birds? Well, the generation 
of the Medusz is at Jeast as marvellous as the fact which we have 
imagined.” Let us note, for example, what takes place with the 
Rose Aurelia, a beautiful Medusa, of a pale rose colour, with nearly 
hemispherical disc, from four to five inches in diameter, whose edge 
is furnished with short russet-brown tentacles; taking for our guide 
the eloquent and learned author of ‘ Metamorphoses in Man and the 
Lower Animals,” M. de Quatrefages. 
The Medusa designated under the name of Rose Aurelia lays 
eggs which are characterised by the existence of three concentric 
