Chart defining developmental stages and expression domains in N. vectensis. (A) The twelve main developmental stages of Nematostella vectensis, according to [24, 25*, 26], Duboc unpublished, *raised at 18°C) and the developmental time required to reach them (in hours post fertilization (hpf), days (d) or month (m)) depending on the temperature of rearing. (B) Schematic representations of the developmental stages indicated in (A) with focus on characteristic stage specific anatomical features and a proposed expression domain nomenclature in order to homogenize database entries. All stages are profile views oriented according to the axis key represented at the bottom of the figure. The nomenclature of the later stage replaces its younger equivalent. For example Animal Plate (AnPl) at the early gastrula stage replaces the term Animal pole (An) at the Blastula stage (both presumptive endoderm). (AbEc) Aboral Ectoderm, (AbHe) Aboral Hemisphere, (An) Animal pole, (AnHe) Animal Hemisphere, (An/Or) Animal/Oral, (AnPl) Animal Plate, (At) Apical tuft, (AtEc) Apical tuft Ectoderm, (AtEn) Apical tuft Endoderm, (BwEc) Bodywall Ectoderm, (BwEn) Bodywall Endoderm, (En) Endoderm, (Ecto) Ectoderm, (L) Left, (M) Mouth, (MeEc) (Mesentery Ectoderm, (MeEn) Mesentery Endoderm, (NSiS) Non-Siphonoglyph Side, (OrEc) Oral Ectoderm, (OrHe) Oral Hemisphere, (pEn) presumptive Endoderm, (PhEc) Pharyngeal Ectoderm, (PhEn) Pharyngeal Endoderm, (R) Right, (Si) Siphonoglyph, (SiS) Siphonoglyph Side, (TeB) Tentacle Bud, (TeBa) Tentacle Base, (TeEc) Tentacle Ectoderm, (TeEn) Tentacle Endoderm, (TeTi) Tentacle Tip, (Ve) Vegetal pole, (Ve/Ab), Vegetal/Aboral, (VeHe) Vegetal Hemisphere.