ACALEPHiE. 
227 
less, some naturalists have rather taken them for ears reduced to their 
“wwt simple expression. 
The Medusae are not absolutely destitute of nervous system. W e 
have seen that they have ganglions and probably optic nerves. 
Ehrenberg also states that they have ganglions at their base, which 
hirnisli them with nervous filaments. 
Without entering further into the details of their delicate and com- 
plicated structure, we shall pause briefly on their mode of reproduc- 
tion. \y e s hall find here physiological phenomena so remarkable as 
to appear incredible, had not the researches of modern naturalists placed 
facts beyond all doubt. “Which of us,” says M. de Quatrefages, 
1 Would not proclaim the prodigy, if he saw a reptile issue from an 
laid in his court-yard which afterwards gave birth to an indefinite 
number of fishes and birds ? Well, the generation of the Medusae is 
a t least as marvellous as the fact which we have imagined. Let us 
note, for example, what takes place with the Lose Aurelia, a beautiful 
Medusa, of a pale rose colour, with nearly hemispherical disk, from 
t'Ur to five inches in diameter, whose edge is furnished with short 
l 'Usset-brown tentacles; taking for our guide the eloquent and learned 
a uth or of the “ Metamorphose in Men and Animals,” M. de Quatre- 
fa ges. 
The Medusa, designated under the name of Hose Aurelia, lays eggs 
'Wick are characterised by the existence of three concentric spheres. 
hese eggs are transformed into oval larvae, covered with vibratile 
c Ws, having a slight depression in front. They swim about lor a short 
t; nie with great activity, much like the infusoria, which they strikingly 
l ' e semble in other respects. 
the end of forty-eight hours the movements decrease. Aided by 
W® depression already noted, the larvae attaches itself to some solid 
( %, fixing itself to it at this point by the assistance of a thick mucous 
Uiatter. A. change of form soon takes place : it becomes elongated ; its 
Pedicle is contracted, and its free extremity swells into a club-like 
Wape. An opening soon presents itself in the centre of this extremity, 
through which an internal cavity appears. Four little mammals have 
n °w appeared on the edge, which are elongated in the manner oi 
ar uas. Others soon follow: these are the tentacles of a polype: the 
y°ung infusoria has become a polype ! 
polype increases by buds and shoots, just like a stiawbeny 
Q 2 
