Monograph . — Ekaterinburg: UrO RAS, 2000. — 130 s. — ISBN 5-7691-166-0The monograph presents the results of research on the structure of the mesonephros (syn. - primary kidney, torso kidney, Wolf body) in embryonic and early fetal periods of prenatal ontogenesis in humans. The light-optical, electron-microscopic, morphometric characteristics of the components of the nephron of the mesonephros are given, the classification of the sections of the tubular part of the nephron is proposed. Stages in prenatal ontogenesis in humans are distinguished, characterized by the peculiarity of the structural organization of its excretory system. Based on the analysis of the literature and the results of their own research, the authors showed , that the Wolf body during the embryonic and early fetal periods of prenatal ontogeny in humans is a vital prophylactic organ, performing excretory and homostatic functions as part of the excretory system of the embryo , involved in embryonic morphogenesis of the sex glands , in the development of determinative hematopoiesis, Initiation and regulation of the laying and growth of limbs. The book is intended for histologists, embryologists, obstetricians. Pediatricians, Urologists, Nephrologists .