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Depending on the species, the blastopore has been reported to become the mouth (protostomy), the anus (deuterostomy), both mouth and anus (amphistomy), or neither (i.e., the blastopore closes).
After about seven cell divisions, the embryo has become a blastula consisting of at least 128 cells. If you were to look inside the blastula, you would see that most of it is empty space. This empty space characterizes the blastula and is called the blastocoel. During the blastula stage of development, two different types of cells are present. The trophoblast is the outer layer of cells, which will eventually become the placenta. The other cells within the blastula are called the inner cell mass.