The resin contains, in addition to the beautifully preserved plant-structures, numerous remains of insects, spiders, annelids, crustaceans and other small organisms which became enveloped while the exudation was fluid.
They are divisible into the Haplodrili or Archiannelida, the Polychaeta containing the marine worms, the Oligochaeta or terrestrial and fresh-water annelids (see Earthworm), the Hirudinea or leeches (see Leech), and a small group of parasitic worms, the 11-Tyzostomida (q.v.).
In external characters the Hirudinea are unmistakable and not to be confused with other Annelids, except perhaps with the Bdellodrilidae, which resemble them in certain particulars.
Pharynx, and he sums up their relationship to the Annelids by thestatement that to a certain extent the Nemertines represent Turbellaria which in the course of time have copied certain features of an Annelid character.
Its integument is marked by a large number of transverse grooves simulating the segmentation of Annelids, and near the anterior extremity close to the mouth are two pairs of recurved chitinous hooks.
How would you define annelids? Add your definition here.