The mouth is beneath the head, and the straight intestine at the posterior and. They have a very singular long tubular proboscis, which can be everted from a pore in the front of the head. Their nervous system and blood vessels are well developed. Some of the species become over one hundred feet long. They are mostly marine and seldom parasitic; a few inhabit fresh water. The two principal divisions are anopla and enopla.
Origin: NL. See Nemrtes.