THE SHELL-FISH OF THE COAST. ya | 
will naturally depend upon the force and quantity of 
the water ejected. This retrograde motion appears 
to be the more general form of movement of the 
animal at such times when it is not actually creep- 
ing about, head downward, along the oceanic floor, 
although through a twisting of the funnel, or even 
by means of the fin attached to the hinder part of 
the body alone, the animal is enabled to pursue a 
forward course as well. The funnel also serves as 
an exit to that very remarkable ink-like substance, 
known as sepia, or true India ink, which is secreted 
by a special glandular body (ink-bag) lodged in the 
body-substance. Most of the cuttle-fishes are pro- 
vided with this inky material, which, indeed, consti- 
tutes their principal weapon of defence. Instead of 
boldly sallying forth to meet their would-be assail- 
ants, wisdom has guided these animals to avoid their 
more powerful opponents, which they do by cloud- 
ing the waters with a heavy discharge of sepia. 
Under cover of the darkness thus produced they 
generally manage to escape. The effect of the 
sepia-discharge not only suffices to discourage 
the enemy, but frequently from its copiousness 
proves deadly to it. I well remember my first 
dredging exploits in the Bay of Naples, when, flushed 
with the excitement attending a rare capture, I un- 
guardedly dropped a cuttle-fish into a tub contain- 
ing my choicest specimens from the deep. In an 
instant the vision of sea-horses, star-fishes, sea- 
anemones, etc., faded off into a cloud of increasing 
blackness, through which no beam of life again 
penetrated to the surface. 
