Fia. 239.—Cuttle-fish (Sepia officinalis) ; 
one-fifth natural size. Atlantic coasts. 
COMPARATIVE ZOOLOGY. 
plete tubular funnel, and an 
ink- bag containing a_pe- 
culiar fluid (sepia), of in- 
tense blackness, with which 
the water is darkened to fa- 
cilitate escape. They have 
the power of changing color, 
like the Chameleon. They 
erawl with their arms on 
the bottom of the sea, head 
downward, and also swim 
backward or forward, usual- 
ly with the back downward, 
by means of fins, or squirt 
themselves backward by for- 
cing water forward through 
their breathing funnels. 
The Paper Nautilus (Ar- 
gonauta) and the Poulpe (Oc- 
topus) have eight arms. The 
female Argonaut secretes a thin, unchambered shell for 
Fie. 240. — Paper Nautilus (Argonauta argo): 1, swimming toward a by ejecting 
water from funnel, b; 2, crawling on the bottom; 3, coiled within its shell, 
which is one-fourth natural size. 
Mediterranean. 
