ORDER ACALEPHA SIMPLICES. 485 
CEPH#ZA, Peron, are distinguished from the other Rhizos- 
toma only by some filaments mixed with the denticulations of 
their pedicle. Medusa Cephea, Forsk., &c. 
The CAssiop# have, properly speaking, no pedicle; 
their arms usually eight in number, sometimes branched, 
spring immediately from the inferior surface. Med. Frondosa, 
Pallas, &c. 
Other species, without a central mouth, have none of these 
numerous ramifications to the pedicle, nor open cavities to 
lodge the ovaries. ‘They may be united under the name of 
ASTOMA. 
Some, however, have still a large pedicle, furnished on each 
side with hairy filaments, which may serve as suckers. 
LYMNOREA and FAVonrA, Per. 
Others have not even these filaments, but a membrane in 
the form of a funnel at the end of the pedicle, and from the 
bottom of which the vessels appear to issue, which ascend 
into the pedicle, and spread out in the umbrella. Geryonia, 
properly so called; Peron. There is one in the Mediterra- 
nean ; Med. proboscidalis, Forsk. xxxvi. 1. 
This membrane is even wanting in others. ORYTHTIA, id. 
Medusa minima, Bart., &c. 
There are some without any pedicle, but in which the under 
part appears furnished with small suckers along the passage 
of the vessels) BERENICE, Peron. Cuvieria eurisochroma, 
Peron. 
Finally, there are some in which no suckers are perceptible, 
the two surfaces being smooth, and without apparent organs. 
Eupora, Peron. 
The Mediterranean possesses a species of these about the 
size of a five-franc piece, and to which the people give the 
name of that coin. Hud. moneta, N. 
When these very simple animals assume more concavity, their 
