In 1967, the present author published as a monograph "Histological studies of the human thyroid gland observed from the viewpoint of its postnatal development" based upon the quantitative measurements of thyroid tissue compo nents in 326 cases ranging in age from immediately after birth to 88 years. Through successive intermediate zones, newborn, infant, child and pubertal on one hand and through a transitional zone presenile on the other hand, the realm of interest concerning in medicine recently has been extended from the main trunk of the adult towards two poles, senile (gerontology) and embryonic (prena talogy). The problem of the thyroid gland is no exception to this recent trend (Boyd, 1950) and also seems to be one of the most topic endocrine subjects from the standpoint of this view (Russel et at., 1957; Carr et at., 1959; Smith et at., 1961; Pickering, 1964; Pickering et al., 1958, 1961, 1963; French et al., 1964). A survey of the literature shows considerable numbers of papers dealing with the developmental histology of the prenatal human thyroid gland. Earlier, Dr.

Materials and Methods

Description and Discussion
I. The Prenatal Development of the Human Thyroid Gland
A. Primordial Development: Early Differentiation Stage (3 to 13 mm CRL, 5 to 7 Weeks)
B. Preparatory Development: Preparatory Differentiation Stage (14 mm CRL to 90 mm CHL, 8 to 12 Weeks)
C. Final Development: Follicle Stage (95 to 520 mm CHL, 13 weeks to full term)
D. Topography of the Follicle Development in the Prenatal Human Thyroid Gland
E. Bloodvessels
F. Connective Tissue
G. Growth of the Human Thryoid Gland in Prenatal Life
H. Feto-Maternal Connection in the Development of the Human Thyroid Gland
I. Human Thyroid Gland in Perinatal Life
II. The Human Ultimobranchial Body in Prenatal Life
A. General in the Comparative Anatomical Viewpoint
B. Prenatal Development of the Human Ultimobranchial Body
C. Epithelial Cells
D. Parafollicular Cells
E. Blood Vessels and Connective Tissue
F. Prenatal Growth of the Human Ultimobranchial Body
G. Chronological Relation Between the Developments of Human Thyroid Gland and Human Ultimobranchial Body
H. Extrathyroidal Human Ultimobranchial Bodies and Those in Thyroid Aplasia and Hypoplasia
III. Others Residuals of the 4th-5th Branchial Pouch Complex Found in the Human Thyroid Gland in Prenatal Life
A. Thymus (IV)
B. Parathyroid (IV) Gland and its Residual Islets
IV. Residuals of the 4th-5th Branchial (Branchial) Pouch Complex Found in the Human Newborn Thyroid Gland
V. Residuals of the Third Branchial Pouch Origin
Summary
References
Addendum.