在许多哺乳动物,出生后很久才开眼,睑外面及内面分化各不相同。外面相当于外面的皮肤,而内面则分化为一种薄弱的结膜。与动物的瞬膜相当的半月襞或可在外眦部显现睑形,乃是残余的第三眦睑,其原基于眼睑粘膜合时即已在内眦处形成。人类属于进化中较为完全的高等哺乳动物,眼睑的原基在第二胎月之初即已建立,第三胎月,其游离 In many mammals, the eye is opened long after birth, and the outer and inner eyelid differentiation varies. Outside is equivalent to the outside of the skin, while the inside is divided into a weak conjunctiva. Half the moon’s equivalent to the instantaneous membrane of the animal or the appearance of the eyelid in the outer part is the third remaining eyelid which has been formed at the inside of the eyelid on the basis of the eyelid mucosa. Human beings belong to the evolution of the more complete higher mammals, eyelid primordium has been established at the beginning of the second fetal month, the third fetal month, the free