Colorized scanning electron micrograph of a human egg. The egg is surrounded by a glycoprotein coat called the zona pellucida which aids in trapping and binding the sperm. Two residual coronal cells f...

Scanning electron microscope image of Lytechinus pictus [sea urchin] embryo at the 16-cell stage. The four large macromeres are behind the four small micromeres. The eight mesomeres are behind the mac...

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 t...