PRONEPHROS

[pro.neph.ros] n [NL, fr. Gk pro- + nephros kidney--more at nephritis] (1881): either member of the first and most anterior pair of the three successive paired vertebrate renal organs that functions in the adults of amphioxus and some lampreys, functions temporarily in larval fishes and amphibians, and is present but nonfunctional in embryos of reptiles, birds, and mammals--compare mesonephros, metanephros -- pro.neph.ric adj