The body wall of Balanoglossus is made up of an outer epidermis, an inner musculature and peritoneum. Epidermis: It consists of a single layer of epithelial cells. The epithelial cells are of tall columnar type and have their nuclei near their broader bases. These cells are mainly of two types: (i) Ciliated epidermal cells are more numerous and each bears [...]
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. [...]