CHAPTER XLIV 

 INTRODUCTION TO THE CLASS OF AMPHIBIANS 



Among the many wonders of Nature, few are more 

 -^ ^ interesting to the thoughtful mind than those forms 

 which connect the great groups of vertebrate animals by 

 bridging over what otherwise would seem like impassable 

 chasms. 



For example, between the classes of Mammals and Birds 

 we have the platypus, or duck-bill, an Australian mammal 

 the size of a small muskrat, which has webbed feet and a 

 duck-like bill, and which reproduces by laying eggs. Be- 

 tween the classes of Birds and Reptiles there is a fossil bird 

 called the Ar-chae-op'te-ryx, with a long, vertebrated, lizard- 

 like tail, covered with feathers. The Hes-per-or'nis was a 

 water-bird with teeth, but no wings, which inhabited the 

 shores of a great western lake which now is a vast stretch 

 of arid bad lands. 



Between the Reptiles and the Fishes stretches a wonder- 

 ful chain of living links by means of which those two Classes 

 are united. So numerous are these forms, they make an 

 independent Class, containing about 1,040 species. Orig- 

 inally this group was called Ba-tra'chi-a, but recently the fact 

 has been recognized that that term is too limited in its appli- 



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