Phylum Ctenophora: General Characters and Classification

Defination 

Ctenophora are marine zooplankton invertebrate and called as sea gooseberries. 

General features 

• Ctenophores are commonly known as sea walnuts or combe Jellies 

• They are exclusively marine.

• They are Diploblastic,radially symmetrical, Acoelomate organisms with tissue level of organisation. 

• The body bears eight external rows of ciliated comb plates  which help in locomotion.

•  Digestion is both extracellular and intracellular. 

• Bioluminescence  is the property of a living organism to emit light,  well-marked in ctenophores. 

• Sexes are not separate therefore they are Monocious 

• Reproduction takes place only by sexual mode.Development is indirect.

• Fertilisation is external with indirect development.

Examples of Ctenophora  

1. Pleurobrachia 

• It is commonly called as sea gooseberries.

• It is a pelagic animal caught in coastal area but some time it is present in intertidal zone. It is widely distributed in all over the world.

• It has two tentacles which are long it's length of body.

• This ctenophora does not show Bioluminesence but has some shining effect.

• It uses Eight  row of comb plate for the movement.

• It is hermaphrodite and has both male and female reproductive organ

• It does not has nematocyst has special cell colloblast for the attachment.

2. Ctenoplana 

• It is commonly called as sea walnut.

• It has reduced nervous system including non polar neurons without synapsis.

• It has two tentacles which are long it's length of body.

• Ctenoplana  show Bioluminesence and it glow in dark.

• It uses Eight  row of comb plate for the movement.

• It is hermaphrodite and has both male and female reproductive organ

• It does  has special cell colloblast  which release stick material to catch the prey.