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POPULAR SCIENCE REVIEW. 
connected with the history of the tribe, “ produce various kinds 
of these singular animals ; they live amidst the Arctic waters of 
Spitzbergen, Greenland, and Iceland ; they swarm under the 
fires of the Equator, while the great Southern Ocean is rich in 
numerous species. All maritime peoples appear to have known 
them from the highest antiquity ; Philippides, Eupolis, Aristo- 
phanes, and Diphilus, before Aristotle, have mentioned them ; 
and from the time of Pliny to our own days (the beginning of 
the 19th century) more than one hundred and fifty writers of 
all the nations of Europe have occupied themselves with their 
history.”* The true interpretation, however, of Medusan 
structure and life has been reached since the French naturalists 
wrote. 
Aristotle, singling out a character which is by no means 
universal, fixed upon the tribe the name of sea-nettles (Acalephce), 
in conjunction with the Actiniae ; and it has clung to the Medusae 
from his time to the present. Many of the species, no doubt, 
sting, and sting severely; but many more seem to be destitute 
of the power, or to possess it in a very slight degree. The 
secretion of a poisonous or paralysing fluid, it may be re- 
marked in passing, has an important relation to the diet of the 
jelly-fish, enabling it to deal with creatures much higher in the 
scale of being, and much more strongly built than itself. Other 
popular names for the Medusae are founded on the phospho- 
rescent properties which many of them manifest, and which form 
so striking a feature of their history. To the Italians they are 
“ Candellieri di mare ;” the Arabs call them “ Kandil el bahr ” 
(lucerna marina'). The resemblance between the rhythmical 
pulsation of the disc and the respiratory movement has sug- 
gested the designation of Pulmo marinus , or “sea-lungs,” 
while our own “jelly-fish” and its less refined equivalent 
“ sea-blubber,” if not'so poetical, are in their way as expressive 
as any.f * 
But turning from names to the things themselves, the Disco - 
jphora constitute an Order of one of the two great branches into 
which the Ccelenterate sub-kingdom divides itself, the Hydrozoa. 
It ranges alongside the Hydroid Zoophytes, as a parallel group ; 
and while the two divisions have their capital features in com- 
mon, they are separated by a sufficiently broad line of structural 
difference. The Hydroid includes within the compass of its 
individuality two principal elements, a fixed alimentary zooid 
or hydra, and a reproductive zooid, which is frequently or- 
ganised for free and independent existence, on the Medusan 
* u Histoire generate des Meduses.” Introduction. 
t Other trivial names are u Gelee de mer,” u Chapeau marin ” (Mediter- 
ranean), u Boule de mer,” “ Capello di mare,” &c. 
