Who were the tribes the Lewis and Clark encountered in North Dakota? Had the Mandan and Hidatsa ever seen an African-American before? How did tribes fare in the wake of the expedition?
The flatworms, flat worms, Platyhelminthes, Plathelminthes, or platyhelminths (from the Greek ÏÎ»Î±ÏÏ, platy, meaning flat and á¼Î»Î¼Î¹Î½Ï (root: á¼Î»Î¼Î¹Î½Î¸-), helminth-, meaning worm) are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates.
This was before the nature of the animals was clearly understood, and both phyla, as then defined, included, in addition to the ectoprocts, organisms not closely related to them. Hence, some workers prefer to use the phylum-name Ectoprocta for the phylum-concept in the narrower sense.Other scholars, however, continue to use the term Polyzoa or Bryozoa in a restricted sense for the phylum that includes the animals that almost everyone calls bryozoans.he creatures now assigned to phylum Ectoprocta originally were referred to phylum Polyzoa by J. V. Thompson in 1830 and to phylum Bryozoa by C. G. Ehrenberg a few months later, in 1831.