Age, 9.6 days.

Standard length, 3.68 mm. Length of caudal fin, 0.32 mm.

Mesencephalon width, 1.00 mm. Depth of yolk, 1.42 mm.

This stage is characterized by the appear-ance of fin rays in the pectoral fin buds. The pericardial extra-embryonic membranes be-gin to split here in the region in front of and between the eyes. This is the first step in the regression of these membranes.