| |
Characteristics |
Class |
| (1) |
Mouth ventral, gills without
operculum; skin with placoid
scales; persistent notochord |
Chondrichthyes |
| (2) |
Sucking and circular mouth; jaws
absent, integument without scales;
paired appendages |
Cyclostomata |
| (3) |
Body covered with feathers; skin
moist and glandular; fore-limbs
form wings; lungs with air sacs |
Aves |
| (4) |
Mammary gland; hair on body;
pinnae; two pairs of Limbs |
Mammalia |
