|
Zygote
|
2-cell stage
|
0:23
|
First cleavage, blastodisc divided via meridional cleavage to form two equal cells
|
1a
|
| |
4-cell stage
|
0:32
|
Second cleavage, dividing the blastodisc into 4 blastomeres
|
1b
|
| |
8-cell stage
|
0:40
|
Third cleavage, 2 x 4 array of blastomeres
|
1c
|
| |
16-cell stage
|
1:02
|
Fourth cleavage, 16 blastomeres can be seen
|
1d
|
| |
32-cell stage
|
1:35
|
Fifth cleavage, 2 regular tiers (horizontal rows) of blastomeres, sometimes in 4 x 8 array
|
1e
|
| |
64-cell stage
|
2:05
|
Sixth cleavage, 64 blastomeres were ranked irregularly
|
1f
|
| |
Morula stage
|
4:05
|
The blastomeres were still distinct but the number of blastomeres can not be counted
|
1g
|
|
Blastula
|
Early blastula stage
|
6:30
|
The blastomeres were no longer distinguishable, the blastocoel began to form, and endoderm germ layer appeared
|
1h
|
| |
Late blastula stage
|
9:40
|
Epibolic cells increased, the archenteron can be seen, endoderm germ layer invaginated and the ectoderm layer formed
|
1i
|
|
Gastrula
|
Early gastrula stage
|
11:36
|
Blastoderm cells begin to spread over the yolk, and blastoderm remains uniform in thickness
|
1j
|
| |
Mid gastrula stage
|
13:45
|
Germ ring epiboled 1/2 of yolk sac, embryonic shield visible from animal pole
|
1k
|
| |
Late gastrula stage
|
15:00
|
75% coverage of the yolk cell by the blastoderm, dorsal side distinctly thicker; epiblast, hypoblast, evacuation zone visible
|
1l
|
|
Neurula
|
embryoid body formation
|
19:47
|
The prototype of the neural plate appeared, head part uplifted, yolk plug exposed, pigments on the embryonic shield and yolk sac can be seen
|
1m
|
|
Pharyngula
|
Formation of optic vesicle
|
22:23
|
On both sides of the head, a pair of kidney-shaped protrusions can be seen
|
1n
|
| |
Appearance of myomere
|
25:46
|
Embryoid surrounded the yolk sac, in the center of the embryoid, 8–11 myomeres can be seen.
|
1o
|
| |
Muscular effect
|
38:35
|
Embryo begins to spin frequently, heart beat 70-75/min
|
1p
|
| |
Pre-hatching stage
|
42:45
|
The embryo shows conspicuous muscular contractions
|
1q
|
|
Hatching
|
newly hatched larva
|
44:05
|
General transparent, floating on the water surface
|
1r
|
