English name: Sea urchin Scientific name: Psammechinus sp. Familia: Echinidae Classis: Echinoidea Phylum: Echinodermata Regnum: Animalia
In the successive cleaving rounds 2, 4, 8, 16, 32, 64, 128 a.s.o. blastomeres are formed. After a while it becomes difficult to track each single cell. This is problably a cluster consisting of 32 cells. To next stage. One stage back.