164 POPULAR OFFICIAL GUIDE. 



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

 shores of the great western lake which has already yielded 

 to American paleontologists a great number of most remark- 

 able fossil forms. 



Between the reptiles and the fishes, stretches a wonderful 

 chain of living links by which those two Classes of verte- 

 brates are so closely and unbrokenly united, and by such 

 an array of forms, that they constitute an independent Class, 

 the Batrachia, or Amphibia. In the transition from water 

 to land, from fins and gills to legs and lungs. Nature has 

 made some strange combinations. In some instances the 

 fins, legs, lungs and gills have become so mixed that several 

 notable misfits have resulted, and in some cases we see gills 

 and legs going together, while in others lungs and fins are 

 associated. 



The Reptile House contains ten species of Batrachians, 

 and it is reasonably certain that this number will be main- 

 tained and increased. They are to be found in small aqua- 

 rium cases, ranged along the south side and eastern end of 

 the Main Hall. 



The Bullfrog, (Rana catesbiana}, is a fair representative 

 of the Batrachians which stand nearest to the true land- 

 going reptiles. During the early stages of its existence it is 

 in turn, a fin-tailed tadpole with no legs, a short-tailed tad- 

 pole with a pair of front legs, a shorter-tailed tadpole with 

 four legs, and finally a fully-developed, land-going frog, 

 with a voice like a small bull, and no tail whatever. Of the 

 genus Rana, there are five species in the eastern United 

 States, several of which inhabit the Zoological Park. 



The Wood Frog, (Rana sylvatica), is frequently seen in 

 moist valleys in the Zoological Park, where its chocolate 

 brown back so closely matches the color of the dead leaves 

 and moist earth; it is difficult to find, save when it takes one 

 of its flying leaps. The specimens shown were taken near 

 the Beaver Pond. 



The Tree Frog, (Hyla pickeringi), is the commonest of 

 the queer little tree-loving species which are so easy to hear, 

 and so difficult to find. In spring their voices are the first 

 to be heard in the swamps. The Zoological Park is full of 

 Hylas, and their cheerful piping is heard at all seasons, 

 especially in dry midsummer, when dark storm-clouds 

 gather and promise rain. 



The Common Toad, (Bnfo lentiginosus), is found in the 

 Zoological Park, though not in such abundance as the two 

 preceding species. 



