배아(Streeter 연령균 XXI)의 1예

Abstract

A human embryo that is thought to belong to age group XXI of Streeter's developmental horizon is described. This embryo was obtained incidentally from the hysterectomy specimen to a 32 years old woman who was operated for ovarian cystic teratomao Tbe length of the embryo was 20. 5mm. It was serially sectioned in 7I'm thickness and reconstructed with 141 section slides. This embryo was characterized by the cornea consisting of three layered compact mesodermal sheet, ependymal remnant in the optic nerve, turning down of the cochlear tip, threadlike stalk of the hypophysis, blind sac of the vomeronasal organ, the submandibular gland with secondary branching of its duct, spoon-shaped Bowman's capsule and clearing center in cartilage of bones. From the above findings, we concluded that this embryo belonged to age group XXI of Streeter's dcvelopm ental horizon.