CEPHALOPODS. 497 
Home asserts the contrary ; and no opportunity presented itself for 
the complete solution of the question, until Poli was placed by the 
King of Naples in a position to solve it. The piscina of Portici was 
placed at his disposal. He witnessed the curious mechanism by 
which the egg is expelled from the egg cavity, and found in it the 
rudiments of a shell, and satisfied himself, by following their develop- 
ment day by day, that the shell existed in the embryo, and grew with 
the animal. He satisfied himself also that the opinion enunciated by 
Aristotle, that at no point did the animal adhere to the shell, was 
perfectly true. 
Finally, in the curious series of experiments carried on by 
Madame Power, in the port of Messina, the fragments of the frail 
bark of the mollusc, which were broken off in taking it, were restored 
in a few days, having been reproduced. It is, therefore, now quite 
demonstrated that the Argonaut, like other testaceous molluscs, itself 
secretes and constructs its shell—its diaphanous skiff. The reader, 
however, must not flatter himself that he can witness with his own 
eyes from the shore, in our narrow channel, the charming picture of 
the Argonaut painted by poets and natural historians: they never 
come near theshore. They are timid and cautious creatures, dwelling 
almost always in the open sea. They live in families, some hundreds 
of miles from the shore; and it is during the night, or at most in the 
fading light of sunset, that they assemble together to pursue their 
gambols on the surface of a tranquil sea. 
However reluctant we may be to destroy the marvellous fictions 
of ancients and moderns, we are compelled to declare that there is no 
truth in the often-repeated statement that the Argonaut uses its pal- 
mated arms as oarsor sails. In order to swim on the surface, it comports 
itself as all other Cephalopods do. Ituses neither oars nor sails, and 
the palmate arms only serve to envelop and retain its hold on its frail 
shell. Its principal apparatus of progression is the funnel with which 
it is furnished, in common with all Cephalopods, and which is very 
long in the Argonaut. Aided by this apparatus, it ejects the water 
after it has served the purpose of respiration, and, in doing so, pro- 
jects itself through the water. While it advances through the water 
under this impulse, its pendent arms, elongated and united in bundles, 
extend the whole length of the shell. Fig. 337 shows the position of 
the different parts of the animal when it thus breasts the waves. These 
arms are also powerful aids when the animal creeps on the ground at 
the bottom of the sea. 
When the animal is disturbed it retires completely into its shell. 
From that moment, the equilibrium being changed, the shell is over- 
GG 
