either of the paired ridges of tissue that run along the dorsal surface of the abdominal cavity of the embryo. Parts of it develop into the kidney, ovary, or testis and their associated ducts. Intermediate stages of these developments are the pronephros, mesonephros, and metanephros.
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a longitudinal cordlike part of the urogenital ridge, formed of fused or never separated nephrotome plates, that gives rise to the mesonephric tubules and part of the metanephric tubules.Medical dictionary. 2011.