In this article we will discuss about the respiratory system of the balanoglossus with the help of suitable diagrams. Branchial Pharynx: Two lateral longitudinal para-branchial ridges divide the pharyngeal cavity into a dorsal respiratory or branchial portion and a ventral digestive portion. Dorso-laterally, on each side, the branchial portion of pharynx is perforated by a longitudinal series of numerous U-shaped [...]
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 [...]