The body wall of cnidarians consists of an outer layer or epidermis, an inner layer or gastrodermis, and a middle layer or mesoglea. Cnidarians lack organs and posses a primitive nervous system known as a neural net. Cnidarians exhibit two basic structural forms, a medusa and a polyp. The medusa form is a free-swimming structure which consists of an umbrella-shaped body (called a bell), a fringe of tentacles that hang from the edge of the bell, a mouth opening located on the underside of the bell, and a gastrovascular cavity.
Tropic of Capricorn, parallel of latitude at 23Â°30â south of the equator; it is the southern boundary of the tropics.This parallel marks the farthest point south at which the sun can be seen directly overhead at noon; south of the parallel the sun appears less than 90Â° from the northern horizon at any day of the year.ropic of Capricorn, parallel of latitude at 23Â°30â south of the equator; it is the southern boundary of the tropics.
â¢ Tropic of Cancer: Encloses the North Temperate Zone with the Arctic Circle. â¢ The Equator: Divides the earth in North and Southern Hemispheres . The are around the Equator is referred to as the Tropics and is limited northward by the Tropic of Cancer and southward by the Tropic of Capricorn. â¢ Tropic of Capricorn: Encloses the South Temperate Zone with the Antarctic Circle. â¢ Antarctic Circle: Is the boundary of the South Frigid Zone to the south.