LIFE SCIENCE

Detailed explanation-1: –Microlecithal eggs are the eggs which contain very little yolk in it but the amount of cytoplasm is high. These eggs are generally small in size as compared to other types of eggs. The eggs of marsupials, amphioxus and eutherian mammals are of this category of eggs.

Detailed explanation-2: -Example-The eggs of sharks, ganoid fishes, Dipnoi, and many amphibians. In these cells, an Enormous amount of yolk is present and here yolk is several times greater than the cytoplasm. These eggs can be small or big.

Detailed explanation-3: -Microlecithal egg: When the egg contain Small or negligible amount of yolk it is said to be microlecithal. E.g.: Amphioxus, Tunicates. III. Mesolecithal egg: In amphibian, Dipnoi and Petromyzon the amount of yolk present is moderate and is not high Hence these eggs are also named as mesolecithal eggs.

Detailed explanation-4: -Microlecithal eggs require minimal yolk mass. Such eggs are found in flatworms, roundworms, annelids, bivalves, echinoderms, the lancelet and in most marine arthropods.