Two major types of meroblastic cleavage are discoidal and superficial. In meroblastic cleavage, the ovum does not split completely. Meroblastic cleavage is the incomplete division of cells. This type of meroblastic cleavage is called discoidal because only the blastodisc becomes the embryo. In bilateral animals cleavage can be either holoblastic or meroblastic depending on the species. The fish zygote is meroblastic, meaning the early cell divisions are not complete.