Cephalopoda. MOLLUSCA. Argonauts. 31 3 
abundant in tlie Mediterranean, as well as the Atlantic 
and Indian oceans, the best known species. The shell 
of this species is a very beautiful object, and the favourite 
of poets and artists of all ages. As Dr. Johnston 
observes, it is the original whence artists have derived 
many a pretty design for the car in which the sea-born 
Venus is made to ride the ocean, and which “sportive 
dolphins drew.” It is the “little Nautilus” of Pope, 
who as a poet improved upon the pretty picture of 
the animal given by Aristotle, who described it as 
floating on the surface of the sea in fine weather, and 
holding out its sail-shaped arms to the breeze. Pliny 
endorses Aristotle’s notion of its raising its webbed 
arms and spreading them, out as a sail ; and the poet 
Montgomery, in his Pelican Island, has since his time 
“ married it again to immortal verse” : — 
“ Light as a flake of foam upon the wind, 
Keel upward, from the deep emerged a shell, 
Sha])ed like the moon ere half her horn is fllled ; 
Fraught with young life, it righted as it rose. 
And moved at will along the yielding water. 
The native pilot of this little bark 
Put out a tier of oars on either side. 
Spread to the wafting breeze a twofold sail. 
And mounted up and glided down the billow 
In hapi)y freedom, pleased to feel the air 
And wander in the luxury of light.” 
The movements of this beautiful mollusc, however, 
are now better known, and have been stripped of the 
fable and poetry which enveloped them. The little 
sailor sits in its boat with its siphon turned towards the 
keel, and its sail-shaped dorsal arms closely applied to 
the sides of the shell — fig. 210. It swims by ejecting 
water from its funnel or siphuncle, and like the re.st of 
the Cuttle-fishes, the motion is backwards, the shell 
being driven in that direction by the recoil caused 
by the sudden and forcible expulsion of the water for- 
wards. Its motions, however, are not confined to 
swimming, as it crawls at the bottom of the water in a 
reversed position, carrying its shell over its back like 
a snail. 
These creatures are very shy and timid. “ During 
calm weather,” says Madame Jeannette Power, “and 
in quiet water, if not feeling themselves observed, they 
make a parade of their many beauties, rowing with full 
sails tinged with beautiful colours, and resting the 
extremities of their sail-arms on the two sides of the 
shell, or embracing the shell with them. It is then 
that their different movements and habits may be 
observed ; but I was obliged to act with the greatest 
caution in order to enjoy this spectacle, for the creatures 
are extremely suspicious, and no sooner find them 
selves observed than they let themselves fall to the 
bottom, and do not rise again for many hours.” Mr. 
Arthur Adams, during the voyage of the Samarang. 
had frequent opportunities of observing two species of 
Argonaut with their living inhabitants, and corrobo- 
rated two facts with regard to their history. He 
observed “ that the female Argonaut can readily dis- 
engage herself from the shell, when the velamentous 
arms become collapsed, and float apparently useless 
on each side of the animal ; ” and ascertained from 
experiment “ that she has not the ability, or perhaps 
the sagacity, to enter her nest again, and resume the 
guardianship of her eggs.” He was satisfied also 
Jb’ig. 210. 
Swimming Argonaut. 
“that the thin shell of the Argonaut is employed by the 
female as a safe receptacle in which to deposit her 
eggs;” for he dissected a specimen of A. tuberculosa 
(A. nodosa) that was taken firmly embracing the shell, 
which contained a large mass of eggs occupying the 
discoidal portion of the chamber and the poslerior por- 
tion of the roof. The eggs he describes as being very 
numerous, and united together by a delicate, glutinous, 
transparent, filamentous web, and suspended to the 
body whirl of the spire. 
Sub-order II. — DEC APOD A (Decapods). 
In this sub-order the body of the animal is elongated, 
oblong, or cylindrical, and always provided with a pair 
of fins. The mantle is supported by a fleshy band, or 
VoL. TT. 96 
by cartilaginous buttons and loops ; and the body is 
strengthened in the middle of the hack by an internal 
shell, which is longitudinal and either horny or cal- 
