In favour of Long Life. 169 



water-salamanders or tritons, which, like frogs in 

 youth, possess gills. They leave the water, lose their 

 gills and develop lungs. If they are prevented from 

 leaving the water, they do not lose their gills. The 

 gills remain and the water salamander continues 

 through life in the same condition as its lower rela- 

 tions, the gilled salamanders, which attain their full 

 size and sexual development, and reproduce without 

 losing their gills. =■' 



The reduction of virile power in the cuckoo males, 

 so that they consent to share the favours of the 

 female ; and the lessening or shrinking — in one of the 

 ovaries (as proved by the production of eggs so much 

 smaller than the eggs of other birds and out of all 

 proportion to size) would, on this line of argument, be 

 in favour of long life in the individual cuckoos ; and 

 on this point there is much room for careful observa- 

 tion. 



XXIII. 



And on what true scientific ground can Mr. 

 Romanes say that the habit of the thrush in taking 

 snails to stones to break the shells, and the flying up 

 of crows and gulls with shell-fish to drop them on 

 rocks or stones so as to smash the shells, " must orig- 

 inally have been intelligent actions purposely designed 

 to secure the ends attained,"t and then deny that 

 originally the habit of the young cuckoo to turn out 

 the true occupants of the nest was a " truly intelligent 

 action purposely designed to secure the ends attained." 



* Haeckel's History of Creation, i, p 241 

 ■'c Animal Intelligence, p. 283. 



