Types of Egg with Examples

I.Types of egg on the basis of amount of yolk
1. Name of Egg: Alecithal
     Amount of Yolk: Negligible of yolk
     Example: Human and other mammals (Placental mammals)
2. Name of Egg: Microlecithal
    Amount of Yolk: Small amount of yolk.
   Example: Echinoderms(Sea urchin), Branchiostoma, Amphioxus, Marsupials
Types of Egg on the basis of amount of yolk
3. Name of Egg: Mesolecithal
   Amount of Yolk: Moderate amount of yolk.
    Example: Lung-fishes, Amphibians (frogs and toads)
4. Name of Egg: Macrolecithal or Megalecithal or Polylecithal
    Amount of Yolk: Large amounts of yolk.
     Example:Sharks, Bony fishes, reptiles and birds
II. According to the distribution of Yolk 
1. Name of Egg:  Iso lecithal or homolecithal
    Distribution of Yolk: Yolk is evenly distributed.
    Examples: Occurs in alecithal and microlecithal eggs. Sea urchin, amphioxus,marsupials,other mammals
2. Name of Egg: Centrolecithal
    Distribution of Yolk : Yolk at the centre of egg, with cytoplasm around it.
    Example: Insects
3. Name of Egg: Telotecithal 
    Distribution of Yolk :Yolk is concentrated on one end of the egg, the vegetal hemi-sphere, with the cytoplasm plus the nucleus concentrated the at other end, the animal hemisphere.
   Examples: Occurs in the mesolecithal and macrolecithal eggs of frogs, toads, birds, reptiles etc. 

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