Figure 1
From: The normal development of Platynereis dumerilii (Nereididae, Annelida)
Schemes of developmental stages of P. dumerilii : zygote, cleaving embryo, stereoblastula - stereogastrula, protrochophore and early trochophore. Left: The scheme indicates the key characteristics of each developmental stage. Right: Next to the scheme a brief summary of the key features for the stage is given. The time points indicated with a star mark the end of each stage and are excluded from this stage. Bold: The name of the stage and in brackets the beginning and end of each stage is given. Italic: The key characteristics, which can be used to determine the beginning of each stage. Normal: Additional features of each stage are given, including some landmarks, which can be seen in the developing nervous system and musculature. From top to bottom: zygote (apical view), cleaving embryo (apical view), stereoblastula - stereogastrula (ventral view, apical up), protrochophore (ventral view, apical up) and early trochophore (ventral view, apical up). Abbreviations see abbreviations list.