1 Showing Comparison of Blastulation in Different Chordates Different Types of Blastula The blastula of various groups of animals differs in form and structure depending upon a variety of factors such as the size of the amount and distribution of yolk etc. (Refer Figure 6.2). Different group of animals are characterized by the presence of different types of blastula, as follows:  Coeloblastula: It is a hollow blastula containing a large spacious blastocoel. Usually, the blastocoel is filled with a fluid containing mucopolysaccharides.