2.+Phylum;+Chordata

3. Class; Actinopterygii Animals in this class are ray-finned fishes, their fins being webs of skin supported by bony or horny spines. Approximate nuimber of species: 24,000 3. Class; Amphibia Amphibia are invertabrates who lay eggs that are not surrounded by a membrane. They are cold blooded and have four limbs. Adult amphibians use their skin for respiration. They have an aquatic larval stage. Approximate nuimber of species: 7,000. 3. Class; Aves Aves are birds. They have feathers, have two legs, are warm blooded, lay eggs and have a vertebrate. There are around 10,000 living species. 3. Class; Mammalia Mammals breath air, have three middle ear bones and hair. The females have mammary glands used to feed young. Most mammals have sweat glands and specialised teeth. According to //Mammal Species of the World// there are around 5,700 species of mammal. 3. Class; Reptilia The word Reptile come from the Latin 'repere' meaning to creep. Reptiles are air breathing animals whose eggs are fertilized within the female's body and are encased in a membrane. They are cold blooded and have scales. There are around 9,500 species of reptile.