A specialize cell unique to the phylum Cnidaria. It contains a capsule-like organelle housing a coiled thread that, when discharged, explodes outward and functions in prey capture or defense.
The unique cephalopod mollusks can be found in the Indian and Pacific Oceans, living in rock crevices and coral reefs. Several characteristics make the nautilus stand out from other mollusks and marine animals. Unlike other mollusks, the nautilus has a hard external shell, which takes the form of a spiral.As the animal grows, it seals off chambers in the shell which fill with gas, making the shell buoyant so that the nautilus can swim.he beauty of the nautilus shell has inspired many beach-oriented establishments or brands to name themselves after it. One example is the Nautical Hotel in Santa Teresa, Costa Rica. Though the design of the hotel itself bears no resemblance to the nautilus shell, the name conveys a sense of paradise.
A parrotlike beak rips the food apart, and a radula (found in most molluscs) further shreds the food. To avoid predators by day, some nautilus linger along deep reef slopes as deep as 2,000 feet (610 m). At night, they migrate to shallower waters and cruise the reefs, trailing their tentacles in search of food.