456 OBSERVATIONS ON THE ANIMALS 
swimming Cephalopoda, with those of the Nautilus, and still more 
the Ammonite and other extinct genera. It is, indeed, an extraor- 
dinary thing to find apparent breaks in the great chain of Nature 
thus supplied from a former, but, in many respects, analogous state 
of existence: but such discoveries can never lose their interest by 
becoming too common. It is asource of pure delight, no less to the 
comparative anatomist than to the more humble student of Nature’s 
works, thus to trace order and a system where such things appear 
least to exist ; and when, as in the case before us, the materials 
have gradually accumulated, and the truth at last comes clearly out 
from among a mass of error, we cannot but be peculiarly interested: 
and the result is well worthy of general attention. 
As we have now pointed out the analogies with other genera, as 
well as the peculiarities in the genus before us, we may give the 
following as a probable description of the animal of the Belemnite. 
It resembled, doubtless, in shape, the conical—or rather nine-pin— 
contour of some kinds of Cuttle-fish yet living ; but as it was pro- 
vided with a strong internal shell, seems to have been, on the 
whole, better defended than they are. Besides the shell, it had a 
siphuncle, often sufficiently large, running through the air cham- 
bers, which, as they were defended by the external shell, neither 
required nor possessed any contrivance for increasing their power of 
resistance. The action of this siphuncle would tend to give the 
possessor great facility in ascending or descending in the watec ; and 
thus the animal might be able to obtain food at various, though per- 
haps not at extreme, depths. The provision of ink, too, the bag for 
its secretion, and the contrivance for its excretion, clearly point out 
a means of escape from enemies ; and we know that these cephalo- 
podous animals, although their suckers and long arms are admirably 
adapted to grasp and convey to the mouth the prey upon which they 
subsist, would nevertheless be left, so far as weapons of offence are 
concerned, utterly helpless against the voracious fish and saurians 
which then abounded in the ocean, and were doubtless their natu- 
ral enemies. Their means of escape must, however, have been to- 
lerably efficacious, as they could at once shelter themselves in self- 
created darkness until the concamerated structure and the siphuncle 
had been brought into action, and the animal had sunk and was 
lost to its pursuers. The modern species—the sepia, octopus, &c. 
—not provided with the additional contrivance of the siphuncle, 
have not, apparently, so many enemies to guard against ; and it 
seems probable that the Nautilus, Ammonite, &c. having external 
shells, are, and were, by them sufficiently protected. 
