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.
Five Basic Characteristics of Fish By Stuart Robertson; Updated April 24, 2017 Fish is an animal category that encompasses many species of water dwellers, and even a few species that do not spend all that much time in the water. There are several basic characteristics that are common to most fish, but only a few, like the presence of gills, can be applied to all fish. In fact fish are the most diverse animal species, among the vertebrates, with 32,000 members according to FishBase, a comprehensive database of information on fish used by researchers and zoologists.