Article: Ciliary hovering in larval lancelets (=Amphioxus).

We raised developing lancelets (Branchiostoma floridae) in the laboratory (6, 7) in 8-cm diameter containers filled to a depth of 6 cm with seawater, and we used a television camera fitted with a macro lens (8) to record behavior at room temperature (23 [degrees] C). Locomotion of the embryos (hatching to 2 days after fertilization) was by the spiral, ciliary swimming that has been described previously (9). In contrast, during the month-long stage of the pre-metamorphic larva, the behavior differs markedly from most previously published accounts, which were often based on gradually starving animals maintained in very shallow dishes. We found that the larvae cultured in ...