1
Oval germinal disk of the rabbit, magnified about ten times.
2
Longitudinal section of the germinal disk of a siskin (discogastrula).
3
The tread, which thus becomes the germinal disk, now has the appearance of an eight-rayed star.
4
First is formed a lens-shaped circular germinal disk.
5
Sometimes it has been called the germinal disk, sometimes the germinal spot, and usually the germinative area.
6
A The germinal disk (h, hf) lies flat on one side of the branchial-gut vesicle (kb).
7
But this small white " germinal disk" is now further developed, and is really the gastrula of the chick.
8
B In the middle of the germinal disk we find the medullary groove (mr), and underneath it the chorda (ch).
9
The germinal disk of the hen's ovum at the beginning of gastrulation; A before incubation, B in the first hour of incubation.
10
There is a brisk multiplication of these at the edge of the germinal disk, especially in the neighbourhood of the sickle-shaped primitive mouth.
11
The germinal layers form a flat germinal disk, the borders of which join together and form closed tubes, separating from the central yelk-sac.
12
In both cases a discoid gastrula with primitive streak arises from the segmented ovum, a two-layered germinal disk with long and small hinder primitive mouth.
13
This gives rise to a dark ring, more or less sharply set off from the lighter centre of the germinal disk (Figure 1.115).
14
Germinal area or germinal disk of the rabbit, with sole-shaped embryonic shield, magnified about ten times.
15
Germinal disk of the lizard (Lacerta agilis).
