In this paper, the morphological development of periderm of the hands and feet of 21 human embryos were investigated. The estimated gestational age (EGA) of the collected specimens were 6-24 weeks.On 36th to 41st days of EGA, the cells of embryonic periderm were seen to be flat and polygonal in shape. Microvilli were seen on the cell surface. At the end of 7th week the cells showed conspicuous central elevations as cobblestones. After 11th week, a large single bleb occurring on the cell surface were observed. At 4th month, the number of the blebs increased and complex blebs were formed. Larger blebs showed infoldings and furrows. Then the blebs disappeared and the cell surface became flat again. The cells of periderm began to shed at 17th week.The development of periderm on the hands appeared earlier than that on the feet. The degree of the development of periderm in different regions of hands and feet may be different. The possible significance of the periderm was discussed.

The surface morphology and histogenesis of small intestine of human embryos (from 6 to 36 weeks) were studied by scanning electron microscopy and light microscopy. The results indicated that some low prominences began to form at 6 weeks of gestation and then transformed to round tuberculum, after that to polygonal column. The finger-like intestinal villi were formed finally at the end of 3 months. There was a apparent proximodistal gradient of the morphological maturation of villi and the histogenesis of intestine from duodenum, jejunum to ileum. Splitted and branched villi were found. From 18 weeks onward, the respective characteristics of villi in the three segments of small intestine appeared. Neutral mucus and sialomucus were mainly secreted by the goblet cells, while sulphomucus was secreted by the goblet cells of ileum during the late gestation. By 6-12 weeks the microvilli of duodenum were shorter than that of jejunum and ileum but they increased in height to 1.4?m at 18 weeks. The height of microvill at jejunum and ileum were 0.8-1.0?m from 14 weeks to 32 weeks. Tufts of thick and long microvilli among short microvilli were found. The formation of villi, secretion of goblet cells and microvilli was discussed.