THE LIVING WORLD. 
27 
of the world, however, development continued until the representative types of 
cephalopods now existing show greater perfection of structure, in their natural 
progression from the simpler towards the complex, as well as notable increase 
in size, with corresponding diminution of numbers. These larger existent 
forms will now be noticed. 
The Sepia, or Cuttle-fish, also called Squid, claims our attention as next 
in the order named, and as being closely allied to the nautilus both in habits 
and appearance, though its power is perhaps a hundred-fold greater. They 
are also divisible into perhaps a dozen species, ranging in size from the 
smallest, pen-shaped calamary, that is often found in schools of thousands, 
to the giant squid measuring from tip of tentacle to tail more than a dozen 
feet. Indeed, it has been claimed by not a few persons, Mr. Beale among the 
number, that the creature grows to the extreme length of twenty feet, with 
power to drag an ox into the water. This animal has a soft, unprotected body r 
bag-shaped, and a curious fleshy appendage issuing from the sides. The head, 
which is about one-half the length of the body, terminates in ten tentacular 
arms, the under sides of which are armed with numerous saucer-shaped suckers 
that are used to seize and hold its prey, and by which it also attaches itself 
firmly to anything it may reach. The eyes are large, and near them issue 
two long feelers destitute of suckers except at the extreme ends, and the power 
that these exert is small, evidently being used by the animal to thrust into 
deep crevices to search out its prey. In a bag located near the heart the 
sepia carries a large supply of ink which he can eject at will, and which by 
discoloring the water effectually hides him from view, thus affording him an 
excellent means for protection against enemies. 
Cephalopoda-Dibranchiata ( Two-gilled ). The name of the class is 
derived from the fact that its members cannot only swim, but they also- 
rival the acrobats in their ability to walk upon their heads, along the bottom 
of the water. The shell is generally internal; the arms, which are provided with 
discs for sucking, ordinarily number from eight to ten. 
The Argonauta represent the eight-armed genus ( Octopoda ), and are named 
after the mythological explorers who went forth in the Argo, and whose 
adventures, after stimulating the Greeks, have added to the treasure of stories 
for our own children, besides furnishing imagery for the poet and the 
orator. 
The Argonauta argo (Paper nautilus ) has no internal skeleton ; two of 
its arms are outstretched and form broad sails, which seem to be unfurled to 
the breeze and used for propelling the animal to which they belong. Oliver 
Wendell Holmes’ poem, called “ The Chambered Nautilus,” is familiar to ever}' 
school-boy and may suggest the enjoyment of beauty, of useful lessons, and 
the inspiration which may be drawn from the animal world. 
As a matter of exact science, it must be confessed that the Argonaut 
does not use his canvas-like appendages as sails, but that their function is 
partly that of holding animal and shell together, and partly the secretion of 
the substance from which the shell is formed. This shell, as doubtless is 
known to many of our readers, is very thin and transparent, flexible, and 
grooved, and so like the earlier forms of ships that it is supposed naval 
architects took their first lessons from the argonaut. The argonaut sometimes 
leaves its shell for brief periods. In repairing any damage to its dwelling, the 
