378 ACALEPHA. 
According to the observations of Messrs Audouin and Milne 
Edwards, these Medusz live in society, or at least are always 
met with collected in great numbers and swimming in the same 
direction with their body inclined obliquely. 
The Cernea, Pér., are only distinguished from the other Rhizos- 
toma by having filaments intermixed with the dentations of the pedi- 
cle(1). 
The Cassiopez have no pedicle, properly so called; their (usually 
eight) arms, which are sometimes ramous, arise directly from the 
inferior surface(2). 
In other species, without a central mouth, we find none of those 
numerous ramifications in the pedicle, nor open cavities for lodging 
the ovaries. They might be united under the name of 
ASTOMA. 
Some however—Lymnorea and Favonia, Pér.—still have a large 
pedicle furnished on each side with fibrous filaments which may act 
as suckers. 
Others—Geryonia, proper, Pér.—are even destitute of these 
filaments, but have an infundibuliform membrane at the extremity 
of the pedicle, from the bottom of which vessels seem to arise that 
ascend into the pedicle and spread out through the umbella. 
One of them is found in the Mediterranean, the Med. probos- 
cidalis, Forsk., XXXVI, 1(3). 
OrtruyiA, Pér. 
Where that membrane is wanting(4). 
(1) Medusa cephexa, Forsk., XXIX; Encyc., XCII, 3, 4;—WMed. octostyla, 1d., 
XXX; Encyc., Ib., 4;—WMed. ocellata, Modeer., Nov. Act. Holm., 1791. 
(2) Med. frondosa, Pall., Spic., X, ii, 1, 3;—Med. octopus, Gm.; Borlasse, XXV, 
16, 17;—Med. andromeda, Forsk., XX X1?—WMed. corona, Id., p. 107?—Rhizostoma 
leptopus, Chamiss. and Eisenhardt, Ac. Nat. Cur., X, p. I, pl. xxviii, f. 1;—Cass. 
borbonica, Delle Chiaie, Mem., I, tab. 3, 4. 
(3) Add Dianée Gabert, Zool, Freycin., pl. 84, f. 2; Geryonia tetraphylla, Cha- 
miss. and Eisenh., loc. cit. f. 2. 
(4) Medusa minima, Baster, Op. Subs., 1i;—Dianée dubaul, Zool., Freycin., pl. 
84, f. 3, which is the Geryonie dinéme, Pér. It is possible that mutilated Geryonie 
(which are often in that condition) may have been taken for Orythyiz. 
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