General characters and affinities of dipnoi?, Structure of integument in different classes of vertebrates, derivatives of integument:- Glands scales, horns, feathers, claws and hairs?

Dipnoi, also known as lungfish, are a group of freshwater fish that have both gills and lungs, allowing them to breathe air. They are characterized by their elongated bodies, large pectoral and pelvic fins, and toothed plates in their mouths for feeding on small invertebrates and plants.

The integument, or outer covering, of vertebrates varies greatly among different classes. In fish, the integument is typically covered in scales made of keratin or bone. In amphibians, the integument is thin and permeable, allowing for gas exchange through the skin. Reptiles have scales made of keratin, which can vary in size and shape depending on the species. Birds have feathers, which are made of keratin and serve to insulate and protect the body. Mammals have hair, which also serves to insulate and protect the body.

Derivatives of the integument include glands, which can secrete oils, pheromones, or toxins; scales, which provide protection and can aid in movement; horns, which are bony protrusions used for defense or display; feathers, which aid in flight and insulation; claws, which are used for gripping and hunting; and hairs, which provide insulation and protection.