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486 CLASS ECHINODERMATA. 
inferior surface becomes interior, and may perhaps be regarded 
as a true stomach. These are the CARYBDEA, Peron. Those 
in whose interior no traces of vessels are perceptible, do not 
properly differ from the hydre, but in size. Medusa mar- 
suptalis, Gm. 
It has been found necessary to separate from the medusz, 
some genera united to_them by Linneus, on very slight 
grounds of relation, such as 
BEROE, Miill. 
They have an oval or globular body, furnished with projecting 
ribs, bristling with filaments or fringe, proceeding from one 
pole to the other, and in which we perceive vascular ramifica- 
tions, and a sort of movement of the fluid. ‘The mouth is at 
one extremity ; in those which have been examined, it con- 
ducts into a stomach which occupies the axis of the body, and 
on the sides of which are two organs probably analogous to 
those which we have called ovaries in the medusa, 
Such is, 
Medusa pileus, Gm. (Globular Beroé) Baster. i. iii. xiv. 
6—7.Encyc. xc. 3, 4, with a spherical body, furnished with 
eight ribs ; two ciliated tentacula, susceptible of a great elon- 
gation, issue from its inferior extremity. Itis very common 
in the north seas, and even in the channel on our coasts, and 
is considered as one of the aliments of the whale. 
According to MM. Audouin and Milne Edwards there ex- 
ists in the axis of these animals a cavity which goes from one 
pole to the other, and which communicates externally by 
means of an inferior aperture, which may be considered as the 
front mouth. In the superior third of this cavity is contained, 
and as it were suspended, a sort of straight and cylindrical 
intestinal tube, which has its external aperture immediately 
at the superior pole, and which supports on each side two 
granular cords (ovaries perhaps). The cavity is filled with a 
