In Balanoglossus, there is no definite endoskeleton but there are four structures of a supporting nature, they are a buccal diverticulum, proboscis skeleton, branchial skeleton, and a pygochord. 1. Buccal Diverticulum: Buccal diverticulum is a hollow pre-oral outgrowth, extending from the roof of the buccal cavity into the proboscis. It was for a long time also called a notochord or [...]
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 [...]