Acorn worm

 Scientific Name: Balanoglossus sp.

Classification

Phylum: Chordata -Dorsal tubular nerve cord, gill-slits and notochord present.

Subphylum: Hemichordata -Marine, enterocoelous coelomate. Notochord confined to head region.

Genus: Balanoglossus

Habit and Habitat: It is a marine animal, adapted for burrowing life in the sandy bottom. The animal lives inside the V-tubes (tubicolous). Most of them live in shallow water but a few go deeper up to approximately 15,000 feet. They burrow slowly by soft proboscis.

Characteristics

1. It measures 10 cm to 2.5 meters, depending on the species.
2. It is a bilaterally symmetrical, triploblastic deuterostome with a worm-shaped body divisible into three regions-anterior proboscis or prosoma, middle collar or mesosoma and posterior trunk or metasoma
3. The proboscis is conical, the collar is funnel-like, while the trunk is cylindrical.

Videos

External anatomy of the acorn worm Balanoglossus, Phylum Hemichordata. Source: YouTube, Alan Holyoak

Watch Underwater Worms Poop — A Lot. Source: YouTube, Nat Geo Wild

References

• Practical zoology vertebrates by S.S Lal
• Wikipedia
• The life of invertebrates by J.Z Young