Ids Kathleen Erion, age 12, of Wichita, Kansas, for her question:
What are cephalopods?
Scientists have classified the members of the animal kingdom in groups and given them fancy names. These scientific names give clues about the bodily structure of the animals. However, they are not much use to most of us because they are not in English, French, Spanish or any other common, everyday language. They are coined from old Latin or Greek words, from the classical languages known to scholars of all nations. This means that a bear, say, may have a dozen different names depending upon whether he is being talked about in English, French or some other everyday language. But he has only one scientific name.
The largest scientific groups are the phyla, meaning the tribes or clans: The singular of this word is phylum and all the animals of one phylum have certain basic features in common. Phylum I is Protozoa, meaning the first animals. All the simple one‑celled animals are protozoans. Each phylum is numbered and is more complex than the one before it, way up to the most advanced which includes all the backboned animals.
Phylum XI is Molluscs, meaning the soft bodied ones. They are animals without internal skeletons. There are about 80,000 mollusks and most of them live in the sea. Some live in fresh water and a few live on damp ground. Most of them have shells and a mantle, which is a layer of cells able to make a shell. Each mollusk has some kind of foot, though you may not recognize it as such.
Like other phyla, Molluscs is subdivided into classes. Class II is Gastropods, meaning stomach‑foot. Snails and slugs are gastropods and they crawl along on a single foot which reaches the length of the stomach. Oysters, clams and mussels belong in the Pelecypoda – or hatchet‑foot class of mollusks.
The most highly developed mollusks are the cephalopods, in the class Cephalopods, meaning the head‑footed ones. A cephalopod has a foot joined directly to his head. He has a number of wavy tentacles also fixed to his head, a pair of staring eyes and often a strong, parrot type beak.
This description should call a number of sea‑going animals to mind. Yes, the octopus, the squid and the cuttlefish are cephalopods, The papery‑shelled nautilus of warm Mediterranean waters is also a cephalopod. If you are very lucky, you may get to see an octopus in a marine aquarium. He is an unusual animal, but you soon see that he is quite handsome. He moves his tapering tentacles as gracefully as a ballet dancer. He changes color with his moods and his keeper tells us that he is very intelligent. His foot is a tube through which he squirts water to jet propel himself through the water.