外胚层

The primitie mouth, or stomodeum, is a slight depression on the surface of the ectoderm.

原始的口（或口凹）是外胚层面的一个轻微的凹陷。

Ectodermal dysplasia appears in two froms, hidrotic and anhidrotic, according to clinical features and hereditary characteristics.

摘要外胚层异常症，依照徵及遗传特性，可分无汗型与出汗型大类。

Bilateral oal thickenings of the surface ectoderm, called nasal placodes, then deelop on each side of the inferior part of the frontonasal prominence.

外胚层面呈双边卵圆形增厚形，然后发展为额隆起的下半部分。