Question

Write general characters of Balanoglossus.

Answer 1

Hint: The phylum Chordata is named for the notochord, a longitudinal, flexible rod between the digestive tube and the nerve cord; invertebrates, this is the spinal column. It includes all animals that share four characteristics, although they might each possess some of them at different stages of their development: a notochord, a dorsal nerve cord, pharyngeal slits, and a postanal tail.

Complete answer:
Balanoglossus is a worm-like Protochordate organism. Balanoglossus is a deuterostome, and resembles the Ascidians or sea squirts, in that it possesses branchial openings, or "gill slits".
General Characters -
-It lives in burrows in the sand of intertidal regions of seawater.
-It is 3 cm. to 2 meters in length. Balanoglossus gigas will grow to 2 meters in length.
-It belongs to the class Enteropneusta of Hemichordata phylum.
-Different species of this genus will show different colours. They may be light brown or yellow or light red in colour. The body is big and is divided into 3 parts. - Proboscis, Collar, Trunk.
-Proboscis: It is a club-shaped structure. It is at the anterior end of the body. Its body wall is muscular. It encloses a coelomic cavity called a proboscis. In this proboscis stomochord, Heart, pericardium and glomerulus are present.
-Collar: It is the middle part. It is a short part. In between the collar and proboscis ventrally a big mouth is present. It is a permanent opening. The collar contains two coelomic cavities.
-Trunk: It is an elongated, posterior part. The body wall is folded hence it gives the wrinkled appearance to the body.
-The alimentary canal is straight starting with the mouth and ending with an anus.
The sexes are separate.
- Various species in this genus may display various colours. They may be bright brown or yellow or light red in colour.

Note:
The Class Enteropneusta (acorn-worms) consists of about 75 species of solitary, unsegmented worm-like invertebrates. It is assumed that the ancestors of acorn worms used to live in tubes like their relatives Pterobranchia, but that they eventually started to live a safer and more sheltered existence in sediment burrows instead. Some of these worms may grow to be very long; one particular species may reach a length of 2.5 metres (8 ft 2 in), although most acorn worms are much smaller. Due to secretions containing elements like iodine, the animals have an iodoform-like smell.