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.
Authorities differ in what they consider a phylum, and in the actual name of the phylum. Despite this, there is agreement on most phyla. Most modern surveys include groups above the phylum: superphyletic groupings based on evidence of common descent. Chordata: the phylum which contains the vertebrates. 2  As with the Arthropoda, some taxonomists regard this as a Superphylum, with three phyla. 3  Here, the chordata has three sub-phyla: 4  Urochordata: the tunicates.