In this article we will discuss about the affinities and phylogeny of balanoglossus. Affinities of Balanoglossus: The position of Hemichordata, in the scheme of classification of animals, has been controversial. In 1814, Sedgwick and Huxley suggested the affinities of Enteropneusta (Hemichordata) with the vertebrates and it was in 1885 Bateson considered this group as a subphylum of the phylum Chordata. [...]
The nervous system of Balanoglossus is of a very primitive type resembling that of coelenterates and echinoderms. Nervous system consists primarily of an epidermal plexus or a layer of nerve cells and nerve fibres lies just below the epidermis. Thread-like processes of the epidermal cells contribute to the network or nerve net. The nervous layer is composed of longitudinal nerve [...]
Balanoglossus is a tubicolous or burrowing and exclusively marine animal. It is found in shallow waters between tide marks along the coast of warm and temperate oceans. Balanoglossus is world-wide in distribution. i. Burrow: Balanoglossus clavigerus is tubicolous living in U-shaped burrows excavated in the sandy bottom. The burrow has two vertical limbs 50 – 70 cm deep and the [...]