18 MAMMALIAN DESCENT. [Lect. L 



off. On the otlicr hand, in the tropics of the Old Worhl, 

 to this day, the brothers of the okl Mammoth have been 

 living in harmony with the Sun ; l)ut they have thro^\^l 

 away their cloaks, and bask, naked, in his l^eams. 



But, during great, sudden changes in the home or 

 feeding-ground of animals, the dilemma has again and 

 again been adaptation or extinction ; in many cases 

 nothing short of metamorijJiosis has saved them from 

 death, and kept them alive in famine. 



Speaking of metamorphosis, I am brought to that 

 wdiich is, evidently, the key to the intricate wards of 

 this long-locked-up problem — I mean the descent of 

 organic tyjies. The metamorphosis of insects — a marvel 

 always fresh and wonderful both to the man of years 

 and to the child — reveals to us the practicall)^ infinite 

 ^possibilities of the modifications that may take j^lace in 

 the lifetime of a single worm-like creature. 



If we were not thoroughly familiar, from our childhood, 

 with the astounding phenomena of insect-transformation, 

 if we only knew the Grub, the Pupa, and the perfect, 

 winged Imago, separately, any assertion of such a possi- 

 bility Ijy some far-seeing biologist, would be treated with 

 contempt, and the l^rand of heresy would be set upon him. 



Such a developmentalist would fare as Bruce, the 

 traveller, fared, when he related his adventures, telling 

 of the sights his eyes had seen — 



" All he gets for liis harangue is — ' Well ! 

 ^Miat monstrous lies some travellers tell.' " 



