抄録
Developmental and histological studies of 21 human embryos (3.5mm-223.0mm CR) were made and the results were as follows.
1) The arytenoid prominence which was an initial sign of the formation of the larynx was seemed to develop by the 3rd or 4th week of fetal life, since it was already found with epithelial adhesion in an 5.5mm CR embryo.
2) Epiglottis was also found in a 5.5mm CR embryo as a small prominence among the primordial arytenoid prominence.
3) Primordium of the laryngeal cavity was formed in a 5.5mm CR embryo.
4) The ciliated cells were recognizable in a 48.0mm CR embryo.
In tthis embryonic life, they were found not only in the epiglottic apex but in the laryngeal vestibulum and arytenoid prominence.
In some embryos of CR 3.5mm-12.5mm, 2 or 3 layers of short collumnar cells were recognized. The free surface of these cells have a deeply stained layer, which are considered to include basal body or basal corpuscle and to be the finding of earlier stage of the cilia formation.
Besides, another type of the ciliated collumnar cell is recognized in the basal layer. They appear on the epithelial surface according to the proliferation of the basal cells.
