MOLLUSCA.—CLASS V. CEPHALOPODA. 281 
tion intermediate between the Gastropods and the Fishes, inasmuch as, 
like the former, they are soft inarticulated masses, and in some instances 
conchiferous ; whilst they have, like the latter, a well-developed head, 
enclosing a semi-cartilaginous skull, a pair of jaws, fins, a tongue, &c., 
with moreover a keen sense of vision and great power of locomotion. 
They do not, however, present that immediate relation, that nicely ad- 
justed affinity with the proximate classes, which is so prominent in most 
parts of the system. Some authors have been tempted to conjecture that 
there is a link of animal creation between the Cephalopods and the Fishes 
which yet remains to be discovered. Lamarck, the great demonstrator of 
the Invertebrates, says, that they are probably not the last of that series; 
and the rather forced affinity which Mr. Owen exhibits between the Nau- 
tilus and the Gastropods proves, on the other hand, that the Cephalopods 
are indeed an isolated group. The Pteropods, which present a more 
simple state of organism than the Gastropods, are nevertheless allied to 
the class of animals under consideration : the abdominal portion of their 
body is enveloped, like that of the Cephalopods, with a sack-like mantle, 
though in a greatly modified degree; and their nocturnal habits, their 
pelagic nature, and the rapidity with which they swim, seem evidently 
to prepare us for the corresponding characters which are so highly indi- 
cated here. 
We find mention of these extraordinary animals in the earliest records 
of natural history ; they were minutely described by Aristotle, and have 
been the theme of naturalists and poets in every subsequent age. Little 
was, however, known of the real nature of the conchiferous portion of 
them until long after the revival of letters; the shells were never found 
with their inhabitants, and the relation between them was not established 
with any degree of certainty until the discovery of the living Nautilus 
by Rumphius. This was, indeed, an important era in the history of the 
Cephalopoda; for no one could have imagined that the Nautilus, to- 
gether with the lost race of Ammonites, were in immediate relation with 
the hideous Cuttle Fish and Calamary. The nature of those polythala- 
mous tenants of a former world, the Ammonites and their multifarious 
congeners, was demonstrated by the discovery of the Nautilus, a solitary 
