part of part of immediately preceded by immediately preceded by occurrent late gastrula stage stage 17 late prism stage The embryo has a distinctive, angular shape due to the elongation of the skeletal rods. The body rods have expended even further compared to earlier stages and the postoral rods support short postoral arm buds. The anterior ends of the dorsoventral connecting rods are also now branched or bent. The archenteron tip is still bent toward the oral ectoderm. At the tip of the archenteron coelomic evaginations start to be apparent, although no gut constrictions are visible yet. The embryo is reddish in color due to the presence of pigment cells within the aboral ectoderm. The animal pole domain is prominent, and it still bears long, immotile cilia. ecao_developmental_stage