472 THE OCEAN WORLD. 
of a heart, with a ventricle and auricle. The shell is secreted by the 
outer edge of the mantle, while its posterior extremity fashions the 
walls of the partitions, which indicate the successive growth of the 
individual. : : 
Fig. 321 represents the shell of Maufilus, with the animal re- 
moved ; the last partition is seen empty, and with the perforations 
through which the siphuncle passes. : 
The genus /Vauti/us inhabits the Indian Ocean and the sea round 
the Molucca Islands. In swimming, the head and tentacles are 
projected from out of the shell. In walking on rocks, they drag 
themselves along the ground, the body upwards, the head and 
Fig. 321.—Nautilus pompilius (Linnzus), 
showing the lower cell and the partition giving passage to the siphon. 
tentacles beneath. They betake themselves frequently to miry 
cavities frequented by fish. It is a much more common occurrence 
to find the empty than inhabited shells of the /Vautdlus at sea. 
This probably arises from its exposure to the attacks of crustaceans 
and other marine animals, which seems to be proved by the mangled 
appearance of the edges of the empty shells thus met with. 
The Pearly Nautilus, Mautilus pompilius (Fig. 322), is said to be 
so common on the Nicobar coast that the inhabitants salt and dry 
its flesh, and store it as provisions. Its shell attains about eight 
inches in its greatest height. This shell is said to be still used by the 
Hindoo priests as the conch with which they summon their devotees 
to worship. It is nearly round, smooth, transversely blazed in its 
posterior part, and entirely white anteriorly. A very fine nacre is 
yielded by this mollusc, which is much used in ornamental cabinet- 
work. The Orientals make drinking-cups, on which they engrave 
