Worms

Worms consist of many types of animals having a long cylindrical tube-like body. They have no arms or legs. Some worms are parasites and live in the bodies of other animals. In size, worms can range from microscopic to 192 feet in length, the marine nemertean. Worms which live outside of bodies usually live in water of some kind or underground. The word comes from an Old English word wyrm. This meant a carnivorous reptile like a serpent or mythical dragon.

Most worms are invertebrates, that is they have no backbones. However, two types of vertebrates are called worms: the amphibian caecilians and the slowworm anguis. This is the Latin word for snake. The invertebrates called worms include roundworms, earthworms, nematodes, flatworms, bootlace worms, arrow worms, priapulid worms, and insect larvae, such as grubs and maggots.

Roundworms and tapeworms live in the intestines of their hosts. They are parasitic worms and are also called helminths. Lungworms live in animals such as fish and cats. If someone is said to have worms, it means that he is afflicted with roundworms or tapeworms. Helminthology is the study of parasitic worms. Deworming is the term for getting rid of parasitic worms in humans and animals. Antihelmintic drugs are used.

In the 1200's, Vincent de Beauvais recorded in his book called Mirror of Nature that the category of reptiles included many egg-laying creatures. Worms were classified in this category. Some others were lizards, amphibians, snakes and other fantastic monsters.

Worms are decomposers. Decomposers take in the dirt, digest it and send it back out. The soil is broken down this way. An earthworm's digestive system is a long tube running from its mouth to the rear of its body.

Worms are divided into three groups. Platyhelminthes have a flat body shaped like a ribbon or leaf. A pair of eyes is at the front of the body. Flatworms, tapeworms, and flukes are in this group. Some of these are parasites.

The phylum Nematoda includes roundworms, hookworms, and threadworms. An example of a threadworm is the vinegar eelworm. It is microscopic. Some threadworms may be three feet long. The Nematodes live in the wet earth, decaying matter, moss, and fresh and salt water. Roundworms can be parasites. People living in tropical climates can get Guinea worms under the skin of their legs and feet.

The phylum Annelida is made up of segmented types of worms. Their bodies are divided into parts or rings. Earthworms and the salt-water bristle worms are in this phylum. Many insect larvae are called worms. Included in this group are woodworms, glowworms, bloodworms, inchworms, mealworms, silkworms and wooly bear worms. The ringworm which attacks people is really a skin fungus, not a worm.

About six thousand species of earthworms exist. Earthworms breathe through their skin because they do not have lungs. They let out a fluid from their bodies which gives them the lubrication to burrow through the earth. Every earthworm is both male and female. Worms mate on the ground. Baby worms come out of the cocoons which hold the eggs. The small worms are fully formed. They reach full size in about one year. They may live up to eight years. It is more common for them to have a lifespan of one to two years. The very large earthworms, up to ten feet long, live only in tropical climates.