Question

In hemichordates, the coelom is
A. Absent
B. Pseudocoelous
C. Enterocoelous
D. Haemocoelous

Answer 1

The coelom that arises from the embryonic wall as a hollow outgrowth. It extends and lines both the sides of the gut i.e. inner and outer side of the body wall by mesoderm.

Complete answer:
Organisms that do not have a post-anal tail or even a notochord are known as hemichordates. They are also known as acorn worms. They are commonly found on the seafloor. They vary in size and feed on small organic feeders. They are also known as filter-feeders. The organisms that belong to this phylum have a modified proboscis. They have a three-fold body division with a preoral lobe, collar, and trunk. They have digestive and reproductive organs. They are bilaterally symmetrical and triploblastic. They have a true body cavity or coelom i.e. it is enterocoelous. The coelom is divided into protocoel, mesocoel, and metacoel that corresponds to the three-body regions. Common hemichordates are Balanoglossus and Saccoglossus.
Additional information: Hemichordates are exclusively marine animals which can be solitary or in colonies. They have a complete digestive tract with a U-shaped or straight tube. They have an open type of circulatory system and they respire through gills. The sexes are separate.
Hence, the correct option is C) Enterocoelous.

Note: Enterocoelous coelom pouches or pinched off from the archenteron of the digestive tract. During the gastrula phase of embryonic development, two pockets are developed in the third germ layer which results in the folding of the endoderm.