ALECITHAL,ISOLECITHAL

1. Types of egg
 In the egg cytoplasm reserve food material is called yolk.
 According to yolk amount eggs are divided into 4 types.
 They are
 1.Alecithal egg:No amount of yolk.Ex-Human
 2. Microlecithal egg: Less amount of yolk Ex-Fish
 3. Mesolecithal egg: Moderate amount of yolk Ex-Frog
 4. Megalecithal egg: More amount of yolk Ex-Bird and Insect

2. Found in humans.

3. Yolk amount is less.It isolecithal. Found in Fishes.

4. Found in frog.

5. Found in Bird and insect.

6. Egg types
 On the basis of distribution of yolk eggs are of three
types
 1.Isolecithal egg,:Yolk uniformly distributed.Ex-Fish
 2.Telolecithal egg:Yolk found towards vegetal pole.Ex-
Frog,Bird
 3.Centrolecithal egg:Yolk found at the centre.Ex-Insect

7. All microlecithal are isolecithal.
Mesolecithal are Telolecithal.
Megalecithal are Telolecithal or Centrolecithal.