Extraembryonic mesoderm migrates through primitive streak to the presumptive yolksac between days 6.5 and 7.0 of gestation.
胚外中胚层在妊娠的第6.5至7.0天之间通过原始条带迁移到推测的卵黄囊。
2
I do not believe, however, that this is normal, since in the wild, young with such a large yolksac probably would not survive without parental protection.
我不相信，不过，这是正常的，因为在野生环境年纪这么大的卵黄囊，也许就不会生存父母的保护。
3
The yolksac and yolk stalk on one of them were well preserved.