Question

Comb plates are found in?
(a) Nereis
(b) Aurelia
(c) Adamsia
(d) Pleurobrachia

Answer 1

Hint: Comb plates are generally found in a relatively smaller phylum of the animal kingdom. They are ciliary appendages found in animals and are used for locomotion.

Complete answer:
Comb plates are found in the members of the phylum Ctenophora. Pleurobrachia is a member of the phylum Ctenophora and thus bears comb plates.
Ctenophores are also known as comb jellies because of the presence of comb plates. Comb plates are nothing but the ciliary appendages present in the animals. There are eight external rows of these ciliated comb plates. They play a crucial role in locomotion, as these Ctenophores are marine animals the comb plates are useful in swimming.

Additional information:
-Ctenophores are a phylum of marine animals and are found all over the world.
-Their body is simple, round, oval, or ribbon-like.
-The animals included in this phylum are invertebrates.
-The body of these animals is biradial symmetrical and they are diploblastic.
-Pleurobrachia belongs to the class tentaculata. A common and important feature of this class is a pair of specialized tentacles as the name suggests. The tentacles are long and feather.
-It is important to note that there are no stinging cells present in Ctenophores

So, the correct answer is, ‘Pleurobrachia’.

Figure: Structure of tentacles

Note:
1) Ctenophores are in fact, the largest animals to use a ciliary locomotion
2) They show the property of bioluminescence i.e they emit light.
3) Ctenophores play an important role in maintaining the ecosystem and make up a majority of the biomass of plankton found in the ocean.
4) Many Ctenophores were first included under the phylum Cnidaria but Ctenophores lack nematocysts and thus the members were put under a separate phylum.