454 
ploy's l^ATURAL HISTOKT. 
[Book IX. 
itching, smarting pain,^''' just like that caused by the nettle found 
on land. Eor the purpose of seeking its prey, it contracts and 
stiffens itself to the utmost possible extent, and then, as a 
small fish swims past, it will suddenly spread out its branches, 
and so seize and devour it. At another time it will assume 
the appearance of being quite withered away, and let itself be 
tossed^^ to and fro by the waves like a piece of sea- weed, until 
it happens to touch a fish. The moment it does so, the fish 
goes to rub itself against a rock, to get rid of the itching ; im- 
mediately upon which, the nettle pounces upon it. Ey night 
also it is on the look-out for scallops and sea-urchins. When 
it perceives a hand approaching it, it instantl)^ changes its 
colour, and contracts itself ; when touched it produces a 
burning sensation, and if ever so short a time is afforded, 
makes its escape. Its mouth is situate, it is said, at the root or 
lower part,^^ and the excrements'*^ are discharged by a small 
canal situated above. 
CHAP. 69. SPONGES ; THE VARIOUS KINDS OF THEM, AND WHERE 
THEY ARE PRODTJCEI) : PROOES THAT THEY ARE GIFTED AVITH 
LIFE BY NATURE. 
We find three kinds of sponges mentioned ; the first are 
Many species of the medusse, Cuvier says, and other animals of the 
same class, the physalus more especially, cause an itching sensation in the 
skin when they are touched. This is noticed also by ^lian, Hist. Anim. 
B. vii. c. 35 ; and by Diphilus of Siphnos, in Athenseus, B. iii. 
•^^ This is true, Cuvier says, and more especially with reference to the 
actiniae. They have the mouth provided with numerous fleshy tentacles, 
by means of which they can seize very small animals which come within 
their reach, which they instantly swallow. 
Cuvier says, that this is the case more especially with the medusae 
and the physali. 
" Ora ei in radice." Aristotle, however, says, Hist. Anim. B. iv. c. 5, 
and B. viii. c. 3, that the sea-nettle has the mouth situate tv fisai^, " in the 
middle of the body." Hardouin attempts to explain the passage on the 
ground that Pliny has made a mistake, in an endeavour to suit his similitude 
of a tree to the language of Aristotle. Cuvier says, that there exists one 
genus or species of the medusae, which appears to feed itself by the aid of 
an apparatus of branches, and is divided into such a multitude of filaments, 
almost innumerable, that it bears a strong resemblance to the roots of a 
tree or vegetable. It is this kind, he says, that he has called by the name 
of " Rhizostomos." 
^1 Aristotle, Hist. Anim. B. viii. c. 3, says the same; though, on the 
other hand, in the Fourth Book, he says that the animal has no excrements, 
although it has a mouth, and feeds. 
Cuvier remarks, that there are a great many more than three kinds 
