| Figure No. |
Developmental stage |
Time of appearance (h) |
Characters |
| 1a |
Fertilization |
00:00 |
Round, transparent and adhesive in nature |
| 1b |
Blastodisc |
00:21±00:01 |
An out growth over the vitelline sphere developed at animal pole |
| 1c |
Two cell |
00:49±00:02 |
First cleavage, where two cells over the yolk sphere was clearly visible. |
| 1d |
Four cell |
01:07±00:04 |
Second cleavage, where blastomeres were clearly visible and counted. |
| 1e |
Eight cell |
01:30±00:06 |
Third cleavage, where little overlapping of blastomeres was observed. |
| 1f |
Sixteen cell |
01:51±00:08 |
Fourth cleavage, where overlapping of blastomeres was observed and were placed in two rows. |
| 1g |
Thirty two cell |
02:04±00:10 |
Fifth cleavage where the blastomeres were visible in 2-3 layers. |
| 1h |
Sixty four cell |
02:32±00:20 |
Sixth cleavage, where overlapping of blastomeres was observed and were placed in 2-3 layers. |
| 1i |
Morula |
03:43±00:33 |
Blastodermal cells were very small due to repeated division and gave a flowery look at the animal pole. |
| 1j |
Blastula |
05:12±01:08 |
Difficult to recognize the blastomers. The blastoderm was compressed and occupied more than half area over the yolk sphere. |
| 1k |
Gastrula |
07:27±01:16 |
Thick layer of blastoderm or germinal ring occupied 3/4th area over the yolk sphere. One end of it was observed broad, which became the future cephalic part of the embryo. |
| 1l |
“C” shape embryo |
09:29±01:24 |
Embryo looked kidney shape over the yolk sphere with clear distinction of head and tail. |
| |
Twitching |
21:30±01:10 |
Tail became free from yolk sphere and beat in quick succession to rupture the egg membrane. |
| 1m |
Hatching |
25:27±01:28 |
The larvae were transparent with straight body and having free swimming capability. |
