Enlist the main salient features of phylum Ctenophora.
The main salient features of phylum Ctenophora are: (i) Ctenophores are marine animals having transparent and flat or oval body shapes. (ii) The polyp phase is absent in the life cycle of ctenophores. (iii) These are bilaterally symmetrical and lack cnidoblast cells. (iv) When the tentacles are present, they are two in number and contain colloblast cells. (v) They move by cilia which join together to form comb plates. There are eight median comb plates. (vi) The gastrovascular cavity is branched and open to the outside by the stomodeum. (vii) They are diploblastic, but the mesoglea differs from that of cnidaria. viii) The presence of special sense organs at the opposite end of the mouth is the main characteristic of this phylum. (ix) They reproduce only by means of sexual reproduction. (x) They do not have a larval phase in their life cycle. (xi) Example: -Ctenophora (Pleurobrachia), ctenophore, ctenoplana, Beroe and Hormiphora.
