Discuss the general characters of the class osteichthyes.

Explanation

The general characters of the class osteichthyes are as follows
(i) The body is divisible into head, trunk and tail. Neck is absent
(ii) Pectoral and pelvic fins act as balancing organs.
(iii) The skin is covered by mucous glands and dermal cycloid, ctenoid or ganoid scales.
(iv) The endoskeleton is bony.
(v) The mouth is anterior. Alimentary canal opens out by anus.
(vi) The respiratory system includes four pairs of gills which are covered by operculum.
(vii) Swim bladder is present. It acts as a buoyancy regulator and enables the fish to stay at a particular depth. Sometimes, it is used as a lung for breathing air.
(viii) The heart is two-chambered having one auricle and the other ventricle.
(ix) There are 10 pairs of cranial nerves.
(x) Exceretory organ is kidney. Nitrogenous waste matter is mostly ammonia.
(xi) Sexes are separate. Fertilization is internal.