Q.2. Discuss the general characters of Ctenophora. Describe is its relationship with Coelenterata.
Ans.2. Resemblance With Coelenterates
1. Radial symmetry
2. Tissue grade of organization
3. Presence of gelatinous mesogloea.
4 Lack of coelom.
5. Presence of a gastrovascular cavity.
6. Diffused nervous system.
7. Absence of respiratory, excretory, and circulatory systems.
8. Presence of statocyst.
9. Endodermal origin of gonads.
Differences
1. Absence of polymorphism, colony formation, and alternation of generations in life-cycle.
2. Absence of nematocysts.
3. Presence of colloblasts over tentacles.
4. Presence of 8 combed plates
5. Presence of stomodaeum.
6. Presence of mesenchymal muscle cells.
7. Cleavage of determinate type.
Advancement over Coelenterates
1. Presence of three germ layers.
2. Mesenchymal muscle cells
3. Complete digestive tract.
4. Apical sense organ.
5. Determinate cleavage.
BSc 1st Year Lower Non-chordates Phylum Ctenophora Sample Model Practice Question Answer Papers