Natural history of Trinidad and Tobago giant leatherback sea turtle ("Dermochelys coriacea"), the hawksbill turtle ("Eretmochelys imbricata"), the loggerhead turtle ("Caretta caretta"), the olive ridley turtle ("Lepidochelys olivacea") and the green sea turtle ("Chelonia mydas") are marine species that either nest on the islands' beaches or frequent their coastal waters. The land dwelling yellow-footed tortoise ("Geochelone denticulata") or Morrocoy as it is locally known is threatened by high levels of poaching in Trinidad. The odd mata-mata turtle ("Chelus fimbriata") is known as a waif (and is possibly a rare inhabitant) of the Nariva Swamp and other southern and eastern coastal river systems in Trinidad. The wood-turtle
History of manifolds and varieties spaces with a differentiable or topological structure, while "variety" refers to spaces with an algebraic structure, as in algebraic varieties. In Romance languages, manifold is translated as "variety" – such spaces with a differentiable structure are literally translated as "analytic varieties", while spaces with an algebraic structure are called "algebraic varieties". Thus for example, the french word "" means topological manifold. In the same vein, the Japanese word "" (tayōtai) also encompasses both manifold and variety. ("" (tayō) means various.) Ancestral to the modern concept of a manifold were several important results of 18th and 19th century mathematics. The oldest