tetragon opter us

[Pref. tetra go no-, and Gr. pteron a wing, a fin. Ichthyology: The type-genus of Tetragon opter in a (q. v.), with about fifty species, from Central America. They are all of small size, rarely exceeding eight inches in length; dorsal in middle of the body, which is oblong or elevated, covered with scales of moderate size; belly rounded. tě-trăg-on-oŭs, a. [Eng.tetragon; -ous.] The same as TETRAGONAL (q. v.). tět-ra-gō-nür-ŭs, s. [Pref. tetragon (o)-, and Gr.our a a tail.] Ichthy.: A genus of At her in ide, with a single species. Body sub-elongate, scales strongly keeled and striated; first dorsal of numerous feeble spines, and continuous with the second. It is a rare fish, more frequently met within the Mediterranean than in the Atlantic. Nothing is known of its habits, but as, when young, it accompanies the Medusæ, it must be regarded as a pelagic form. At a later period of its existence, it probably descends to greater depths, coming to the surface only at night. It attains a length of about eighteen inches.