CLASS V. CEPHALOPODA. ORDER I. POLYTHALAMIA. 285 
in that very remarkable quadruped, will very rapidly change colour ; it 
is covered in most of them with a number of pigmental spots or papille, 
and the variety of fixed hues which they will often exhibit in a compara- 
tively short period of time is remarkable *. 
The Cephalopoda should undoubtedly be divided according to the strict 
variations of the soft parts, the modifications of the branchie, the fins, 
the tentacles, &c.; but as we have only to treat in this place of such as 
are conchiferous, we must follow the old arrangement of Breynius, adopted 
always by Lamarck, in which those with chambered shells are separated 
from those in which the shell is not chambered, after the following man- 
Mer: 
PoLYTHALAMIA. MonorTHaLaMIA. 
Order I. CEPHALOPODA POLYTHALAMIA. 
Testa multilocularis, vel interna, vel externa, septis numerosis divisa ; 
septis aut siphunculo, aut foraminibus, perforatis. 
The Polythalamia, or many-chambered Cephalopods, are divided into 
two families, according to the manner in which the chambers into which 
their shell is divided are perforated; in one group it is by means of 
a continuous siphon, in the other by an irregular number of simple 
perforations. The latter division is however inserted here, upon very 
* The extreme voracity of these animals is powerfully described by Mr. Owen in speaking 
of the Octopus, a naked Cephalopod and the largest of the class. “Those alone,” says that 
accomplished writer, “‘who have witnessed the persevering activity, power, and velocity of 
motion exercised by the Octopus, when engaged in its destructive practices amongst a shoal 
of fishes, and who have seen it with its beak buried in the flesh of a victim held fast in the 
irresistible embrace of its numerous arms, in an instant simultaneously dissolve the attach- 
ment of its thousand suckers, and, disengaging itself from its prey, dart like an arrow from 
the net that has been cautiously moved towards it for its capture, can form an adequate idea 
of the acuteness of visual perception and powers of action with which this singular and un- 
shapely Cephalopod is endowed.” —Trans. Zool. Soc. vol. ii. part i. 1838. 
VOL. II. Zap 
