

A CHAPTER ON CUTTLE-FISHES. 259 
or mantle, like a bag fitting tightly tothe back but loose in 
front. It is closed up to the neck, where it is open like a 
loosely fitting overcoat, buttoned up to the throat. Attached 
to its throat, by the middle, is a short tube open at both 
ends.. This tube, or siphon as it is called, is fastened to its 
throat, and can be moved about-in any direction. 
The animal breathes by means of gills, which are attached 
to the front of the body inside the cloak and look like the 
ruffles of a shirt bosom. By means of these gills the air con- 
tained in the water is breathed, and they answer the same 
purpose for the cuttle-fish that our lungs do for us. 
n order to swim, the animal swells out the cloak in front 
So that the water flows in between it and the body. Then it 
closes the cloak tightly about the neck so that the only way 
the water can get out is through the siphon. Then it con- 
tracts very forcibly its coat, which, it must be remembered, 
is a part of the animal, and the water is driven out in a jet 
from the siphon under the throat, and the body is propelled 
in the opposite direction; that is, backward like a rocket 
through the water. This siphon is flexible like a water-hose, 
and can be bent so as to direct the stream not only forward, 
but sidewise and backward, so that the animal can move in 
almost any direction, or turn somersets with perfect ease, 
. and so rapidly do some cuttle-fishes swim that they are able 
to make long leaps out of the water. Usually, however, the 
animal swims backward, with its long arms trailing behind. 
Our common cuttle-fish of this coast has, in addition to its 
eight arms, two long slender tentacles which may be with- 
drawn into the body. The tail is pointed, and furnished 
With a fin on each side. 
The Octopods, to which the Brazilian cuttle-fish (Fig. 45) 
belongs, have round purse-like bodies, and eight arms united 
yy the base with a web, and they swim by opening and shut- 
ting their arms like an umbrella ; in this mode of swimming 
ay resemble the jelly-fishes. . 
Ae paper Nautilus is nothing in the world but a female 
