Figure 4. Transverse section of the posterior part of the amphioxus nerve cord showing the location of different cell types: A translumenal calcitoninergic cell (yellow), a translumenal prolactinergic cell (orange), ependimal catecholaminergic (red), prolactinergic (pink) and follicle stimulating hormone-like (black) cells. (redrawn from Obermüller-Wilén, 1984).