somite (metamere) In a vertebrate embryo, a series of bilaterally paired blocks of mesoderm tissue longitudinally flanking the notochord. There are three distinct tissues within a somite: the dermatome, which will develop to form deep portions of the skin; the myotome, which will form voluntary muscle; and the sclerotome which occurs close to the notochord and gives rise to the vertebrae. See also METAMERIC SEGMENTATION.

somite Any of a series of segmented blocks of tissue in animal embryos that develop from the mesoderm. In vertebrate embryos they lie on the dorsal side of the notochord and give rise to the vertebral column, ribs, dermis, and striated muscle. In invertebrates showing metameric segmentation the somites give rise to the body segments.