Classification 



without skull, vertebrae, ribs, jaws, or limbs, but 

 possessing a notochord, which is, as it were, the promise 

 of the spinal column in the higher vertebrates. 



2. Craniota, animals with skulls, vertebrae, etc. 



The subphylum Craniota embraces the following 

 classes : 



Class i. Pisces — Fishes. 



Class 2. Amphibia — Newts, Frogs, etc. 



Class 3. Reptilia — Lizards, Snakes, etc. 



Class 4. Aves — Birds. 



Class 5. Mammalia — Mammals, including Man. 



From this survey we are enabled to see the relative 

 positions of the Amphibians and Reptiles in the Animal 

 Kingdom, and it will be observed that in the scale, or 

 tree, of life-forms, the Reptiles, for various reasons, 

 occupy a higher position than the Amphibians. Both 

 classes have a very ancient lineage, but it is probable 

 that Amphibians came into existence before Reptiles. 

 Fossil remains indicate that both existed far back in 

 geological time, but Amphibians have been traced as far 

 back as the Carboniferous (coal-bearing) strata, which 

 are older than the Permian rocks, in which the first 

 fossil traces of Reptiles have been discovered. We 

 have reason to think that Amphibians were the 

 dominant animals in Carboniferous times ; some kinds, 

 now extinct, then attained large proportions. The 

 erstwhile dominant Amphibians, however, in time lost 

 their ascendancy, and gave place to the Reptiles, which 



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