Acanthocephala

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Spiny-Headed Worm, a common name for members of a phylum of about 500 species of intestinal parasites that attach to a host by means of spines on an extensible proboscis. They lack a gut and circulatory system and absorb nutrients through the body wall. Adults have separate sexes and live in the intestines of vertebrates. Their eggs are shed with the host's feces and are eaten by invertebrates, into whose tissues the larvae burrow. When the invertebrates are eaten by vertebrates, the latter serve as new hosts. Spiny-headed worms do considerable damage to various fishes, birds, and mammals, including some domesticated animals.

Scientific classification: Spiny-headed worms make up the phylum Acanthocephala.

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