English name: Sea urchin Scientific name: Psammechinus sp. Familia: Echinidae Classis: Echinoidea Phylum: Echinodermata Regnum: Animalia
Multicellular stage (probably 128 blastomeres). While cleavages proceed a so-called morula (morula = mulberry) is formed. In this stage the cytoplasm of the fertilized egg cell is compeltely divided over the blastomeres. Notice that this group of more than 100 cells is of about the same size as the original fertilized egg cell. To next stage. One stage back.
