Fig. 1. Establishment of the primary PLL (posterior lateral line) system during zebrafish embryogenesis, at 48 (A), 55 (B) and 72 (C,D) hours after fertilisation. The earliest neuromasts belong to the anterior lateral line system (A). The embryonic PLL develops progressively between 55 (B) and 72 hours (C,D). Newly formed neuromasts are arrowed and labelled in black, neuromasts formed previously are marked in grey. ALL, anterior lateral line neuromasts; D1-2, dorsal neuromasts; L1-8, lateral neuromasts; O1, occipital neuromast; MLL, middle lateral line system. Anterior is towards the left and dorsal is upwards.
