معنی کلمه :‌ tetractinellida

A division of Spongiae in which the spicules are siliceous and have four branches diverging at right angles. Called also Tetractinellinae.

One who lives either north or south of the tropics, as contrasted with one who lives on the other side of them; -- so called because at noon the shadows always fall in opposite directions (the one northward, the other southward).