GUINEA-WORM (Dracontiasis), a disease due to the Filaria medinensis, or Dracunculus, a filarious nematode like a horse-hair, whose most frequent habitat is the subcutaneous and intramuscular tissues of the legs and feet. It is common on the Guinea coast, and in many other tropical and subtropical regions, and sometimes amounts to an epidemic. The black races are most liable, but Europeans are not exempt. The worm lives in water, and appears to have an intermediate host for its larval stage. It is doubtful whether the worm penetrates the skin of the legs directly or enters the body by the mouth as a larva.