pronephron

Century Dictionary and Cyclopedia

1. n. A part of the primitive kidney of the lower vertebrates, which appears at the most anterior end of the archinephric duct before the rest of the kidney and at some distance from it. It consists of a number of coiled tubuli, beginning with ciliated infundibula or nephrostomata: its duct is the Müllerian duct. See mesonephron.