CIL:39786

Scanning electron microscope image of Strongylocentrotus drobachiensus [sea urchin] at the gastrula stage. Embryo was split open to reveal a nice cross-section through the outer epithelial layer and the blastocoel cavity. The fertilization envelope dissolves during swimming blastula stage; therefore, cilia and microvilli can be seen at the apical end of the epithelial layer. A few migrating primary mesenchyme cells can be seen within the blastocoel matrix. This is a lower magnification of CIL:39790. This image is part of a group of SEM images of sea urchin embryos at various stages of development. The group is available as CIL:39782-39791.