Question

Identify the correct combinations with reference to their larval forms.
A. Holothuroidea – Ophiopluteus
B. Asteroidea – Bipinnaria
C. Pelecypoda – Glochidium
D. Cephalopoda – Auricularia
I. (A) and (D)
II. (B) and (D)
III. (C) and (D)
IV. (B) and (C)

Answer 1

Echinoderms and Mollusks have external fertilization and indirect development. They undergo metamorphosis. In addition, the larva of starfish is Bipinnaria and the larva of Unio is Glochidium.

Step by step answer: Holothuroidea – Ophiopluteus
The larva of Holothuroidea is Auricularia. Holothuroidea includes sea cucumbers. Holothuroidea is tube-like echinoderms. On the other hand, Ophiopluteus is the larva of Ophiuroidea. These are the snake-like echinoderms consisting of the starfish.
Asteroidea – Bipinnaria
The larvae of Asteroidea are Dipleura, Brachiolaria, and Bipinnaria. Asteroidea is the star-like echinoderms that consist of the starfish or the Asterias.
Pelecypoda – Glochidium
Pelecypoda is also known as Bivalvia. The larva of Bivalvia or Pelecypoda is Glochidium. Bivalvia consists of mollusks like Unio.
Cephalopoda – Auricularia
The larva of Cephalopods is known as Paralarva. Cephalopods are members of the phylum Mollusca. These mollusks have no hard shell. Cephalopods consist of Octopus, Squids, and Loligo. On the other hand, Auricularia is the larva of Holothuroidea. Holothuroidea includes sea cucumbers. Holothuroidea is tube-like echinoderms.
Hence, the correct answer is option IV

Note: Mollusks and Echinoderms are both unisexual animals. Their gametes are released in the water where external fertilization occurs. The fertilization causes the development of the zygote. The development of the zygote is indirect with intermediate larval stages. The larva progresses into the adult later on.