Biology of Finfish and Shellfish

4.12.3. Nauplius II

4.12.3. Nauplius

MTL: 0.31 mm (0.29-0.32 mm); MW: 0.17mm (0.15-0.18 mm); MFS: 0.14 mm (0.13-0.15mm)

Setae on appendages plumose; no change in number of setae on A1, but outer terminal and outer lateral setae distinctly smaller than in Nauplius I, inner distal rudimentary seta of nauplius I transformed into a short seta; exopod of A2 with an additional rudimentary seta on outer distal margin, the 4th seta counting from the proximal end bifurcates this bifurcate condition is retained in later naupliar substages; Md comparatively longer; furcal setae show a faint demarcation at proximal 1/3; duration of this sub stage is 3 to 4 hours.