Structure of Nautilus Shells (With Diagram) | Zoology

In this article we will discuss about the structure of Nautilus Shells with the help of a diagram.

1. The present specimen is the dry shell of Nautilus.

2. Nautilus is marine and cosmopolitan animal and is commonly called “pearly nautilus” and it is found in deep coastal waters.

3. The shell is spirally coiled and is divided into a large animal chamber and about 20 small chambers separated by semicircular partitions, which are perforated by narrow tubular apertures through which pass the tubular prolongation of visceral mass —the slphuncle.

4. All chambers except the animal chamber are filled with air and thus help in floating.

5. Mouth is surrounded with numerous lobes with double rows of retractile tentacles

6. Arms and suckers are absent, but gills (ctenidia) and kidneys are two pairs each.

7. Body divisible into a distinct head and a sac­like trunk. The head bears a pair of eyes and tentacles.

8. Nocturnal in habit and feeds on crabs etc.

9. Because of beautiful yellow and brown zebra-like stripes on outer surface and because of pearly inner surface it is widely, used for decoration purposes.