Question

Balanoglossus is commonly known as
A)Peacock worm
B)Acorn worm
C)Sand worm
D)None of the above

Answer 1

Hint: Balanoglossus is an exclusively marine animal. It is a Hemichordate and is considered as an evolutionary link between vertebrates and in-vertebrates. It possesses special features which help the animal in burrowing.

Complete answer:
To solve this question, we must know about the features of Balanoglossus.
The Balanoglossus is considered as a connecting link between the vertebrates and invertebrates. They belong to Hemichordate as they do not have a post anal tail and notochord. The notochord is present in the upper part of the body but does not have a nerve cord.
The front end of this organism is in the shape of acorns. It uses its acorn which has muscular proboscis and collar which helps in burrowing into sand or mud. So it is commonly named as an Acorn worm.
Peacock worm- Sabella pavonina is commonly called the peacock worm. It is a marine polychaete. It has a feather flower like fan which is coloured. So it is known as peacock worm.
Sand worm-Arenicola marina is commonly known as sand worm. It belongs to phylum Annelida. These worms cause infection to other animals.

Hence, the correct answer is option (C)

Note: The acorn worm is a sluggish animal which has a long proboscis. The proboscis is capable of elongation and contraction. It is the most active part of the body which helps in burrowing. It has a stomochord which is a flexible hollow tube found in hemichordates. It is connected with proboscis and communicates with the oral cavity.