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10. Kingdom Animalia eLearn.Punjab
Superclass Pisces
This super class includes classes, cyclostomata, chondrichthyes and osteichthyes. The class
cyclostomata includes most primitive living vertebrates which are without jaws. This distinguishes
them from the rest of the vertebrates. They are represented by the lampreys and hagfish. Some of
their characteristics are as follows:
1. Body is long eel-like. 2. Scales absent.
3. No paired appendages. 4. Cartilaginous Skeleton.
5. Ventral Suctorial mouth. 6. Heart with one auricle.
7. Six to fourteen pairs of gills. 8. Digestive system lacks stomach.
9. Sexes are separate in lampreys. Hag fishes are hermaphrodite.
10. Fertilization external and there is a long larval period in Lamprey.
Fig. 10.15 Lamprey
Class Chondrichthyes
This group includes the sharks and rays which have skeleton of cartilage but have many resemblances
to the bony fishes, the cartilaginous skeleton is considered a degeneratedjbharacter rather than
primitive character. Their main features are:
1. Body fusiform.
2. Mouth ventral olfactory sacs not connected to mouth cavity.
3. Placoid scales on the body.
4. Endoskeleton entirely cartilaginous.
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