ANATOMY

Detailed explanation-1: -Two major types of meroblastic cleavage are discoidal and superficial. In discoidal cleavage, the cleavage furrows do not penetrate the yolk. The embryo forms a disc of cells, called a blastodisc, on top of the yolk.

Detailed explanation-2: -Meroblastic cleavage takes place in the presence of a large amount of yolk in the fertilized egg cell and its two types are discoidal and superficial cleavage.

Detailed explanation-3: -Meroblastic cleavage takes place in those eggs where the amount of yolk is high, which leads to the partial or incomplete cleavage. It is basically of two types spherical and discoidal. The discoidal type of cleavage takes place in the reptiles and birds whose eggs are telolecithal in nature.

Detailed explanation-4: -(embryology) A meroblastic cleavage wherein mitosis occurs without cytokinesis, resulting in many nuclei, which migrate to the periphery of a centrolecithal egg.

Detailed explanation-5: -Discoidal cleavage is commonly found in birds, reptiles, and fish which have telolecithal egg cells (egg cells with the yolk concentrated at one end). In superficial cleavage, mitosis occurs but not cytokinesis, resulting in a polynuclear cell.