What is Ctenophora?
Animals that are marine, floating as solitary one, jelly-like transparent body with longitudinal ciliated comb plate without any nematocysts are known as ctenophora.
What are the characteristic feature of ctenophora?
The main characteristic feature of ctenophora are as follows:
i) All members of this phylum are marine and solitary.
ii) Their body is soft, transparent, bi-radially balanced and jelly-like.
iii) The body is enclosed by eight ciliated comb plate that are equidistant and longitudinally placed. Cilia of the comb plate are helping in locomotion.
iv) Tentacles if present are two in number. They are solid and retractile.
v) Nematocysts are absent in ctenophora; but the tentacles are provided with special type of cells known as Lasso cells or colloblast. They are helping in food catching.
vi) There is mesenchyme with muscle fibers that is being situated below the ectodermal layer ; hence they are regarded as triploblastic animals.
vii) Though they are triploblastic yet the coelom is absent in their body.
viii) Excretory, respiratory and blood vascular systems are absent.
ix) Nervous system is loosely arranged with an opposite end of mouth aperture sense organ.
x) Ctenophora are all hemaphrodite and asexual reproduction is absent.
If there have any importance of Ctenophora?
The ctenophora are not doing any direct benefit to man but many of the species are utilized in research work.
What are the difference between Cnidaria and Ctenophora?
1) The Cnidaria are diploblastic animals whereas Ctenophora are triploblastic animals.
2) In Cnidaria cnidoblasts with nematocysts are present but in Ctenophora Nematocysts are absent but lasso cells are present.
3) In Cnidaria ciliated comb plates are absent and in Ctenophora ciliated comb plates are present on the outer surface of the body.
4) Polypand medusoid forms are present in Cnidaria, but Polyp forms are absent in Ctenophora.
5) Asexual and sexual both types of reproduction are present in Cnidaria, whereas only sexual reproduction is present in Ctenophora.