\Nem`er*ti"na\, n. pl. [NL. See {Nemrtes}.] (Zo["o]l.)
An order of helminths usually having a long, slender, smooth,
often bright-colored body, covered with minute vibrating
cilia; -- called also {Nemertea}, {Nemertida}, and
{Rhynchoc[oe]la}.
Note: 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.