Fig. 4.

Apical organ regeneration in Mnemiopsis leidyi cydippids. A Schematic representation of the time course of morphogenic events during cydippid’s apical organ regeneration. Cartoons correspond to lateral views of the apical sensory organ at different stages of regeneration. B–C’ DIC images of the apical organ of an intact cydippid in lateral (B, B’) and aboral (C, C’) views. D Schematic of the components of the apical sensory organ in lateral (D) and aboral (D’) views. E–L’ DIC images showing the cut site of regenerating cydippids after apical organ amputation from 12 to 60 hpa. Lateral and aboral views are included. Dotted line rectangles delimit the area corresponding to higher magnifications on the right. Filled and empty white arrow caps in G’ point to aggregation of cells forming the primordia of the future statolith and apical organ floor respectively. N > 100. Scale bars = 100 μm. Abbreviations: hpa hours post amputation, we wound epithelium, ec endodermal canal, dc dome cilia, l lithocyte, sc supporting cilia, ao fl apical organ floor, cf ciliated furrows