Question

Paddle worm amongst the following is
A. Arenicola
B. Chaetopterus
C. Sabella
D. Amphitrite

Answer 1

Hint: Paddle worm belongs to the family Chaetopteridae of the phylum Annelida that lives within a parchment-like U-shaped tube and is luminescent. In this animal, tentacles and gills are absent.

Complete answer:
Option (A) is incorrect. Arenicola is also known as lugworm or sandworm that belongs to the class Polychaeta of the phylum Annelida and is known for burrowing itself in the sand. This animal has pairs of feathery gills.
Option (B) is correct. Chaetopterus is commonly called paddle worm that belongs to the family Chaetopteridae of the phylum Annelida. It lives within a parchment-like tube and the body is divisible into an anterior region, middle region, and posterior region. Its parapodia have been modified into pumping fans, sucking discs, and food ball organs according to their function.
Option (C) is incorrect. Sabella is commonly called peacock worm that belongs to the family Sabellidae of the phylum Annelida. This animal has a crown of feathery tentacles that protrude out when the animal is submerged but is retracted when the animal is above water.
Option (D) is incorrect. Amphitrite is commonly called an ornate worm that belongs to the family Terebellidae of the phylum Annelida. This animal has three bright red bushy gills and a spread of long tentacles above them.

Hence, the correct answer is option (B).

Note: Chaetopterus is commonly called a paddle worm that is a marine polychaete. In this animal, asexual reproduction takes place by transverse fission and also the parapodia are modified accordingly to their function into pumping fans, sucking discs, and food cups.