1.During early proembryo stage, the dorsiventrality appears in the proper of the embryo. On the ventral side, the cells are small with dense cytoplasm and few vacuoles.
原胚初期胚体出现背腹极性，腹面的细胞小，细胞质稠密，液泡较少；
2.During early proembryo stage, the dorsiventrality appears in the proper of the embryo. On the ventral side, the cells are small with dense cytoplasm and few vacuoles.
原胚初期胚体出现背腹极性，腹面的细胞小，细胞质稠密，液泡较少；