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The velvet worms (Onychophora — literally "claw bearers") are a minor ecdysozoan phylum with ~180 species. These obscurely segmented organisms have tiny eyes, antennae, multiple pairs of legs, and slime glands. They have variously been compared to worms with legs, caterpillars, and slugs. Most common in tropical regions of the Southern Hemisphere, they prey on smaller animals such as insects, which they catch by squirting an adhesive mucus. In modern zoology, they are particularly renowned for their curious mating behaviour and for bearing live young. The two extant families of velvet worms are Peripatidae and Peripatopsidae. They show a peculiar distribution, with the peripatids being predominantly equatorial and tropical, while the peripatopsids are all found in what used to be Gondwana. Formerly considered part of Tracheata, velvet worms are now considered close relatives of the Arthropoda and Tardigrada, with which they form the taxon Panarthropoda. This makes them of palaeontological interest, as they can help reconstruct the ancestral arthropod. ==Anatomy== Velvet worms are segmented creatures with a flattened cylindrical body cross-section and rows of unstructured body appendages known as lobopods (informally: stub feet). The animals grow to between 0.5 and 20 cm (.2 to 8 in), with the average being about 5 cm (2 in), and have between 13 and 43 pairs of legs. Their skin consists of numerous, fine transverse rings and is often inconspicuously coloured orange, red or brown, but sometimes also bright green, blue, gold or white, and occasionally patterned with other colours. Segmenting—outwardly inconspicuous and identifiable only in the regular spacing of the pairs of legs—is visible in the regular arrangement of skin pores, excretion organs and concentrations of nerve cells. The individual body sections are largely unspecialised; even the head develops only a little differently from the abdominal segments. Segmentation is apparently specified by the same gene as in other groups of animals and is activated in each case, during embryonic development, at the rear border of each segment and in the growth zone of the stub feet. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Onychophora」の詳細全文を読む スポンサード リンク
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