Ectoderm and entoderm in this region with the intervening mesodermal layer form the cloacal membrane (Fig. 21).
This double disposition of the cloaca is accomplished by gradual changes in the entoderm and mesoderm.
The inner layer we call the entoderm, the outer the ectoderm; and the "primitive mouth" is known as the blastopore.
The terms ectoderm and entoderm were introduced by Allman in 1853 for the two cell-layers in the Hydrozoa.
They are developed from the entoderm of the third and fourth branchial grooves.
The two layers of the gastrula may now be spoken of as ectoderm and entoderm.
In our bodies only the lining of the mid-intestine and of its glands has arisen from the entoderm.
The growth of the entoderm is another instance of specialized development.
Also almost any part of the animal containing both ectoderm and entoderm can be cut off and will develop into a new animal.
The body consists of two layers of cells, the ectoderm on the outside and the entoderm lining the digestive cavity.
entoderm en·to·derm (ěn'tə-dûrm')
Variant of endoderm.