254 THE WORLD OF THE SEA. 
or too small for its shell; even this would be sufficient reason 
for asserting that the creature was not a robbing depredator, but 
a quiet possessor of his own lawful mansion. But, besides this, 
the egg of the argonaut is found to contain the germ of the shell, 
which increases with the growth of the creature; and cases have 
been known where a broken shell has been repaired by its occupant; 
at once setting the question at rest. Pliny, and the naturalists for 
long after him, believed that the argonauts spread their sails to 
THE COMMON NAUTILUS. 
(Nautilus Pompilius.) 
the wind, and used their other six arms as oars. This, however, 
is scarcely the fact; the arms seem to be used by the creature to 
hold itself in its shell; and its chief motive power is the tube 
from which the water it inhaled for its respiration is ejected, the 
violent expulsion of the fluid propelling the shell forward. When 
in fear, it gathers in its sails and its arms; this overbalances the 
shell, and it sinks to the bottom. 
The nautilus is even more curious and elegant than the 
argonaut. Its shell is a beautiful structure, extremely delicate 
and fragile; its exterior is ornamented with bands, or tongues, 
of a reddish yellow; its interior is richly nacred. The shell is 
