Figure 4

Late development of the caudal fin muscles in the zebrafish. At 6.4 mm SL, the lateralis superficialis dorsalis (a) and interradialis caudalis (b) are formed. The ventral caudal muscle is shifted backward and attached to the proximal caudal bones and vertebrae. At 6.7 mm SL, the inerfilamenti caudalis dorsalis and ventralis are formed and the development of the caudal musculature is complete (c).