GERARD PEAUCELLIER, ISM / SCIENCE PHOTO LIBRARY GERARD PEAUCELLIER, ISM / SCIENCE PHOTO LIBRARY
Sea urchin embryo development. Differential interference contrast light micrograph of a sea urchin (Paracentrotus lividus) embryo at the end of the blastula (hollow ball of cells) stage of development. Following fertilisation an embryo undergoes multiple rounds of mitotic cell division, each time doubling the number of cells. Eventually a blastula of hundreds of cells is produced (seen here), which then start to differentiate. Here, differentiation has begun and the cells of the secondary mesenchyme, which will form the urchin's spicules (spines), are visible inside the blastula cavity. Magnification: x305 when printed at 10 centimetres wide.
Model release not required. Property release not available.