Biology of Finfish and Shellfish (2+1)

4.11.4. 2^nd Stage

The rudiments just described earlier becomes more prominently. On the outer and posterior sides of the rudiments of the funnel, the rudiments of the two posterior pairs of arms first appear, then those of the third and fourth pairs. The first indications of the head are seen in the form of a large double swelling on each side as the outer and anterior part of which carries on each side as the rudiment of the eye. The embryo becomes covered with cilia. At the extreme anterior end the mouth appears in the middle line, forming the opening of the oesophagus, which begins to sink inwards.