Comparative Embryology of Eleven Species of Stony Corals (Scleractinia)
Figure 2
Development of Galaxea fascicularis.
(A) Eggs (pinkish orange, below the line in the lower left corner) and pseudo-eggs (lighter in color, above the line, upper right corner). (B) True eggs are featureless and appear more dense and (C) a section reveals that they are filled with small lipid bodies. In contrast, pseudo-eggs appear vacuolated (D) and the lipid is localized to much larger bodies (E). (F) 2-cell stage. (G) 4-cell stage. (H) 8-16 cell stage. (I) Morula stage. (J) Bowl stage (concave side up). (K) Bowl stage (embryo shown in J-viewed from above). (L) Glancing section of an embryo comparable to J and K. (M) Enlargement of the embryo shown in L, with two sizes of lipid-containing bodies. It appears that the large arise by fusion of the small. (N) Spheroidal embryo with closing blastopore showing center filled with lipid. (O) Mesoglea is gradually forming at this stage. (P) Whole mount of stage similar to O. Red pigment localized at the animal pole as the result of a marking experiment persists in G, H, J, K and P. The asterisk in L and N marks the blastopore.