CEPHALOPODS. 
471 
In tlie last cell of the shell (Fig. 329) is the animal, covered by its 
mantle, which covers the walls of the cells. When it contracts itself 
it is protected by a Sort of 
triangular and fleshy hood. 
Numerous contractile ten- 
tacles, re-entering into the 
sheath, some of them fur- 
nished with numerous la- 
mellae, surround the head, 
which is, besides, scarcely 
distinguished from the 
body. The head bears two 
great projecting eyes, 
planted upon a peduncle. 
Like Sepia and Octopus, the mouth of the Nautilidse is aimed with 
mandibles, fashioned like the parrot’s beak ; the branch he are four in 
Humber. The circulating system consists of a ventricle and auricle, 
und the locomotive tube is protected in its whole length. The shell 
m secreted by the outer edge of the mantle, while its posterior ex- 
tremity fashions the walls of the cells, which indicate the successive 
growth of the individual. 
The siphon, which traverses all the chambers, receives and protects 
the ligament, by the aid of which the Cephalopod is retained in the 
last chamber of the shell. 
Fig. 330 is the same section, with the last cell empty, and with the 
Perforations through which 
the siphon passes. 
The Nautilidse are inha- 
bitants of the Indian Ocean 
a nd the sea round the Mo- 
lucca Islands. In swimming, 
their head and tentacles are 
Projected from out of the shell. 
In walking on rocks they drag 
themselves along the ground. Fig. 330. Nautilus pompilius (Linnaeus), showing the 
II , 0 - , lower cell and the partition giving passage to the 
L11 e body upwards, the head. waterspout. 
a nd tentacles beneath. They betake themselves frequently to miry 
cavities frecpiented by fish. It is a much more common occurrence to 
Fig. 329. Nautilus pompilius (Linnaeus), showing the in- 
terior of the lower cell, to which the animal is fixed like a 
waterspout. 
