opoda--_as the cuttle-fish, the squid, and the octopus. But they
are the only existing members of the group which possess chambered,
siphunculated shells; and it is utterly impossible to trace any
physiological connection between the very peculiar structural characters
of a cephalopod and the presence of a chambered shell. In fact, the
squid has, instead of any such shell, a horny "pen," the cuttlefish has
the so-called "cuttle-bone," and the octopus has no shell, or, at most,
a mere rudiment of one.

Nevertheless, seeing that there is nothing in nature at all like the
chambered shell of the Belemnite, except the shells of the _Nautilus_
and of the _Spirula,_ it was legitimate to prophesy that the animal
from which the fossil proceeded must have belonged to the group of the
_Cephalopoda._ _Nautilus_ and _Spirula_ are both very rare animals, but
the progress of investigation brought to light the singular fact, that,
though each has the characteristic cephalopodous organisation, it is
very different from the other. The shell of _Nautilus_ is external,
that of _Spirula_ internal; _Nautilus_ has four gills, _Spirula_ two;
_Nautilus_ has multitudinous tentacles, _Spirula_ has only ten arms
beset with horny-rimmed suckers; _Spirula,_ like the squids and
cuttle-fishes, which it closely resembles, has a bag of ink which it
squirts out to cover its retreat when alarmed; _Nautilus_ has none.

No amount of physiological reasoning could enable any one to say whether
the animal which fabricated the Belemnite was more like _Nautilus,_ or
more like _Spirula._ But the accidental discovery of Belemnites in due
connection with black elongated masses which were: certainly fossilised
ink-bags, inasmuch as the ink could be ground up and used for painting
as well as if it were recent sepia, settled the question; and it became
perfectly safe to prophesy that the creature which fabricated the
Belemnite was a two-gilled cephalopod with suckers on its arms, and with
all the other essential features of our living squids, cuttle-fishes,
and _Spirulae._ The palaeontologist was, by this time, able to speak as
confidently about the animal of the Belemnite, as Zadig was respecting
the queen's spaniel. He could give a very fair description of its
external appearance, and even enter pretty fully into the details of its
internal organisation, and yet could declare that neither he, nor any
one else, had ever seen one. And as the queen's spaniel was found,