Definition of "pronephros" []

• A kidneylike organ, being either part of the most anterior pair of three pairs of organs in a vertebrate embryo, disappearing early in the embryonic development of higher vertebrates, but functioning as a kidney in some simple vertebrates, such as the lamprey. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The anterior part of the kidney, called the pronephros, disappears in the later larval stages."
• "College, and now are arranged, numbered, and registered in order for use, there is evidence that in 1858 he, with his needles and eyeglass, had dissected and carefully figured the so-called pronephros of the"
• "The pronephros disappears very early; the structural elements of the mesonephros mostly degenerate, but in their place is developed the genital gland in association with which the Wolffian duct remains as the duct of the male genital gland, the Müllerian as that of the female; some of the tubules of the metanephros form part of the permanent kidney."