It is not due to any abnormal development of blood-vessels in the dermis.
The epiblast also forms the epidermis; not however the dermis, which is of mesoblastic origin.
The line of junction between the epiblast and the mesoblast coincides with that between the epidermis and the dermis.
A papilla of the dermis makes its appearance, the outer layer of which gradually calcifies to form the dentine and osseous tissue.
A small papilla of the dermis grows into the inner end of the epidermic process when the hair is first formed.
The eccentrically elliptical pierces the epidermis at right angles, and lies perpendicularly in the dermis.
Each placoid element consists of a spine with a broadly expanded base embedded in the dermis.
These last surround the central mass or core formed by the dermis.
Derma, or Dermis, is the true skin lying under the epidermis (cuticle), which is known in contrast as the scarf-skin.
There remains the dermis or second layer of skin which is also of value for identification purposes.