ALTERNATION OF GENERATION IN CNIDERIA

2. Alternation of generation is also
known as metagenesis.
The phenomenon in which asexually
repruducing polyp alternates which
sexually rèproducing medusa in called
alternation of generation.

3.  There are two body forms in the
life history of most cnidarians.
These are
i. Polyp
ii. Modusa

4. The polyp is usually asexual.
 It is sessile.
 It attaches to a substrate at the aboral end.
 It has a cylindrical body, called the column.
 lt has mouth surrounded by food gathering
tentacles.

5. 2) Medusa (Plural Medusae)
It is a sexual.
It is dioecious.
It is free-swimming.
Its shape is an inverted bowl
Tentacles are on its margins.
The mouth openings is centrally
located lacing downward.
.

6. Alternation of generation:
In Alternation generation of cniderian the asexual
polyp produce male or female medusa , as a result
sexual reproduction form zygote which
transformers into planula larvae which fix itself to a
substrate and finally form a
new asexual polyps.