FBOGS, TOADS AND SOME FftESH-WATEB FISH. 169 



There are, however, a few sheets of clear water, where the weeds 

 grow rank, and where an infinite variety of crustaceans, molluscs, in- 

 sects and! the higher forms of life that prey upon them and each other 

 may be seen and studied with ease. Such stretches occur in some 

 of the marshes to the east of Pao-ting Fu and in the San-chia-tien 

 Lake further lown the Ta-ching Ho. Sometimes also the flooded parts 

 round this settlement are sufficiently clear to render them interesting, 

 while many of the rivers towards their sources in the mountainous 

 areas are beautifully transparent. 



The subject of this chapter, however, is not so much the lower 

 forms of aquatic life, interesting though they may be, but rather 

 a few of the higher forms, belonging to that great group, the cold- 

 blooded vertebrates, but one branch of which (the reptiles) has as 

 yet come under our notice. 



First, then, let us take the amphibeansi, or batrachians, as present 

 day Zoologists prefer to call them : those remarkable creatures, whose 

 lives begin in a sphere of jelly, laid by a solicitous parent in the cool 

 depths of some pond or permanent stream, go through a period of fish- 

 like existence, and finally, developing limbs, discard the fish-form 

 for that of a dry land quadruped. Has the reader ever thought what 

 a wonderful life history that is? It is more than a life-history, it is the 

 history of a race. First the protoplasmal sphere, then the tiny noto- 

 chord and first primitive muscles of the earliest type of fish, followed 

 by a development of gills, eyes, viscera and other adjuncts of a higher 

 piscine form. Next the growth of limbs, absorption of the gills and 

 sealing of the gill slits, and at last the disappearance of the tail, the 

 expansion of the mouth and the completely changed mode of life. 

 In the growth of a few short weeks is illustrated the development 

 and evolution, through countless cycles, of a highly specialized and 

 distinct organism, to wit the common frog. 



Anyone, who has sufficient time to get a good sized bottle, and 

 secure a pair of spawning frogs may witness the whole of this interesting 

 process, and an instructive pastime it will prove. 



There is not a great variety of frogs in North China, very few dis- 

 tinct species having been recorded. We have none of the little tree 

 frogs and other peculiar kinds found in the tropics. The 

 edible frog (Rana esculenta) is very common especially in the 

 marshy districts. It is known to the Chinese as T'ien-chi (field 

 chicken), doubtless on account of its edible qualities. It is sold in 

 the markets of Tientsin at the rate of two for one cent, and cooked 

 s 22 



