40 THE RIDDLE OF THE HERON'S TOE 



gannets, cormorants, pelicans, ibises, spoonbills, etc. ; the 

 storks belonging to the Gruiformes or crane-like birds, 

 which comprise the rails, cranes, bustards, and many other 

 outwardly dissimilar birds. 



Now I have printed the above note at length, for it 

 supplies an example of the amusement to be got out of 

 hunting down the solution of an apparently simple pheno- 

 menon, and, at the same time, its difficulty. The note, 

 much as it stands here, was communicated to a Scottish 

 journal, without much hope of obtaining any light upon a 

 peculiar feature in the heron's foot which hitherto had 

 baffled the acumen of anatomists, biologists, and all the 

 intellects which have been concentrated upon the struc- 

 ture and habits of birds. But I have had better luck than 

 could have been reckoned on. A correspondent from 

 Falkirk sends me a suggestion which commends itself as 

 the simple but satisfactory solution of the puzzle. He 

 believes that the function of the saw-like inner edge of 

 the toe-nail is to prevent the foot slipping upon slimy 

 surfaces when the bird goes a-fishing. Accuracy of aim 

 is indispensable to the heron in pursuit of a darting, slip- 

 pery prey, and such accuracy would be impossible without 

 a secure foothold. Does any one wish to test the truth of 

 this ? Let him try to wade with smooth soles upon the 

 rounded pebbles of a river channel or upon shingle coated 

 with seaweed. He will find that it is all he can do to keep 

 on his feet, let alone attempting to capture fish. All 

 wading equipment must be heavily ironed ; and while I 

 thank my Falkirk correspondent for his timely suggestion, 

 I blush for my own sluggish imagination which failed to 

 recognise in the roughened toe-nail of the heron a con- 

 genital equivalent to human hob-nails. 



