3 o6 THE ROLL OF THE SEASONS 



except here and there an imaginative child who thinks 

 it a shame that he, too, cannot have a lovely plunge- 

 bath. Under him is painted the discouraging word 

 " hybrid," and lower down in very small print " three- 

 quarter polar and one-quarter brown." Ah, there is his 

 secret ! Not merely is he a hybrid, but the descendant 

 of a fertile hybrid, the browner mongrel in the next 

 cage. The mark of a natural species, says the anti- 

 Darwinians, is the sterility of its hybrids, the limita- 

 tion of domesticated varieties, their fertility when 

 interbred. Our polar bear with a brown streak on its 

 back compels them either to say that brown bear 

 and polar bear are one or to forgo a favourite argu- 

 ment against Darwin's theory of the origin of 

 species. 



" Hidden in sight " is a favourite game in the insect- 

 house. We have many times seen a visitor look into 

 a cage and .declare it empty, when it has contained 

 twenty or thirty stick-insects. By the kindness of the 

 keeper we hold one of these in the hand. Even to 

 the touch it seems a stick with smaller sticks glued to 

 it by the edges for legs. At one end the dead wood 

 has apparently been broken off roughly. The older 

 the insect is, the blacker and older seems the wood of 

 which it must be made. The young " sticks," in shape 

 exactly like their parents, court or defy destruction 

 by waving their tails over their heads like scorpions. 

 Probably their agility saves them while they are 

 young ; their resemblance to inedible morsels when 

 they grow staid. The keeper, having enjoyed our 

 wonder at the stick-insects, shows us his land-crabs. 

 He points out that one claw is larger than the other, 

 that being the one most used for feeding. Then, in 



