● This class includes `color{Violet}"Jaw less fishes"` (false - fishes). They have a sucking and circular mouth without jaws.
● `color{Brown}"Mode of Nutrition"`: All living members of the class Cyclostomata are `color{Violet}"ectoparasites"` on some fishes .
● `color{Brown}"Habitat"`: Most of the members of this class are `color{Violet}"marine"` but migrate for `color{Violet}"spawning"` to fresh water. After spawning within few days they die. Their larvae, after metamorphosis, return back to Ocean.
● `color{Brown}"Respiration"`: Their body bears `color{Violet}"6-15 pairs"` of `color{Violet}"gills slits"` for respiration.
● `color{Brown}"Body"`: They have `color{Violet}"elongated body"` which is devoid of scales and paired fins.
● `color{Brown}"Digestive system"`: Stomach is absent. Intestine has spiral `color{Violet}"typhlosole"` (ridges inside the intestine to increase surface area for nutrient absorption).
● `color{Brown}"Circulatory system"`: Circulation is closed type, Heart is two – chambered called `color{Violet}"Venous - heart"`.
● `color{Brown}"Skeletal system"`: `color{Violet}"Notochord"` and `color{Violet}"vertebral column"` both are present. Cranium and vertebral column are `color{Violet}"cartilaginaus"`. Bones are absent.
● `color{Brown}"Tail"`: Tail is `color{Violet}"protocercal"` type. In this type of tail , notochord is extended at the last end of tail and tail fin is divided into two equal dorsal and ventral lobes.
● `color{Brown}"Development"`: Animals are `color{Violet}"unisexual"`; fertilization is external and larval stage absent. Exception: `color{Violet}"Ammocoete"` larva is found during development of Petromyzon.
● `color{Brown}"Examples"`: Petromyzon (Lamprey) and Myxine (Hagfish).
● This class includes `color{Violet}"Jaw less fishes"` (false - fishes). They have a sucking and circular mouth without jaws.
● `color{Brown}"Mode of Nutrition"`: All living members of the class Cyclostomata are `color{Violet}"ectoparasites"` on some fishes .
● `color{Brown}"Habitat"`: Most of the members of this class are `color{Violet}"marine"` but migrate for `color{Violet}"spawning"` to fresh water. After spawning within few days they die. Their larvae, after metamorphosis, return back to Ocean.
● `color{Brown}"Respiration"`: Their body bears `color{Violet}"6-15 pairs"` of `color{Violet}"gills slits"` for respiration.
● `color{Brown}"Body"`: They have `color{Violet}"elongated body"` which is devoid of scales and paired fins.
● `color{Brown}"Digestive system"`: Stomach is absent. Intestine has spiral `color{Violet}"typhlosole"` (ridges inside the intestine to increase surface area for nutrient absorption).
● `color{Brown}"Circulatory system"`: Circulation is closed type, Heart is two – chambered called `color{Violet}"Venous - heart"`.
● `color{Brown}"Skeletal system"`: `color{Violet}"Notochord"` and `color{Violet}"vertebral column"` both are present. Cranium and vertebral column are `color{Violet}"cartilaginaus"`. Bones are absent.
● `color{Brown}"Tail"`: Tail is `color{Violet}"protocercal"` type. In this type of tail , notochord is extended at the last end of tail and tail fin is divided into two equal dorsal and ventral lobes.
● `color{Brown}"Development"`: Animals are `color{Violet}"unisexual"`; fertilization is external and larval stage absent. Exception: `color{Violet}"Ammocoete"` larva is found during development of Petromyzon.
● `color{Brown}"Examples"`: Petromyzon (Lamprey) and Myxine (Hagfish).
