Give the general characteristics of the vertebrates. List the general characters of class cyclostomata.

Explanation

Class-cyclostomata includes round mouthed fishes. They are most primitive living vertebrates. Important feature of members belongs to this class are given below :
(i) Body is long, eel like, deviod of scale, without paired fins.
(ii) Median fins is present, which is supported by cartilaginous fin rays.
(iii). Endoskeleton is cartilaginous. Notochord persists throughout life. Girdles are absent.
(iv) Respiration occurs through gills.
(v) Circulatory system is closed type.
(vi) There are 10 or 8 pairs of cranial nerves.