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A Handbook of Biology

SÜPËRÇLÅSS PÏSÇËS (FÏSHËS)

Class Chondricthyes

Class Osteichthyes

Marine. Stream-lined body.

Predaceous.

Marine & fresh water. Stream-lined

body.

Cartilaginous endoskeleton.

(NEET-I 2016)

Notochord is persistent throughout

life.

Bony endoskeleton.

Ventral mouth.

Terminal mouth.

Gill slits without operculum. Powerful

jaws.

4 pairs of gills covered by

operculum on each side.

Skin with placoid scales. Teeth are

modified placoid scales which are

backwardly directed.

Scales are cycloid, ctenoid etc.

No air bladder. So, they have to swim

constantly to avoid sinking.

Air bladder for buoyancy.

Poikilotherms (cold-blooded).

Poikilotherms (cold-blooded).

Two-chambered heart (one auricle

and one ventricle).

Two-chambered heart (one

auricle and one ventricle).

Sexes are separate. In males,

pelvic fins bear claspers. Internal

fertilisation. Many of them viviparous.

Sexes are separate. External

fertilization. Mostly oviparous.

Development is direct.

Examples

Scoliodon (Dog fish), Pristis (Saw

fish), Carcharodon (Great white

shark), Trygon (Sting ray has poison

sting), Torpedo (Electric ray has

electric organ).

Examples

Marine: Exocoetus (flying fish),

Hippocampus (sea horse)

Fresh water : Labeo (Rohu), Catla

(Katla), Clarias (Magur)

Aquarium : Betta (Fighting fish),

Pterophyllum (Angel fish).