Question

The characteristic larva of Ctenophora is
A. Cydippid
B. Veliger
C. Nauplius
D. Trochophore

Answer 1

Hint: Voracious predators are Ctenophores, variously known as comb jellies, sea gooseberries, sea walnuts, or venus's girdles. They lack stinging cells, unlike cnidarians, with whom they share some superficial similarities. Instead, ctenophores possess sticky cells called colloblasts to trap prey.

Complete answer:
The order of comb jellies is Cydippida. They are differentiated by their circular or oval bodies from other comb jellies, and the fact that their tentacles are branched and can be retracted on either side of the pharynx into pouches. It is the characteristic larva of Ctenophora. It is a free-swimming larva that resembles adults of the order Cydippida. They have bodies more or less rounded and sometimes spherical.
a) Veliger: The veliger is the distinctive larva of the taxonomic groups of gastropods, bivalves, and scaphopods. It is developed following the development of either the embryonic or trochophore larval stage.
b) Nauplius: The larva, called a nauplius, does not differ greatly from the adult in the way of life or means of locomotion in crustaceans but has fewer appendages than the adult. There are three pairs of legs and an unpaired easy eye on a typical crustacean nauplius.
c) Trochophore: A trochophore is a kind of planktonic aquatic larva free-swimming with many bands of cilia by moving rapidly their cilia. They regulate the course of their movement in this way.

Hence, the correct answer is option A.

Note: The Cydippid have two retractable tentacles. For several sea snails and freshwater snails, aquatic, and freshwater gastropod molluscs, Veliger is a planktonic larva. The crustacean larva is Nauplius. The free-swimming larvae of marine annelids and of most classes of molluscs are Trochophore.