12 



cassell's book of birds. 



and feet seem to be better suited to this purpose. The only organ of touch about which there can 

 be no doubt is the bill, yet even this is generally covered with a hard sheath of horn. Nevertheless, in 

 some races the extremity of the bill is soft and largely supplied with nerves. In snipes and wood- 

 cocks, for example, the sensitive extremity of the beak materially assists in procuring their food. 



For the systematic arrangement of the class of birds, the confonnation of their feet has been 



found to afford characters of great importance to the ornitho- 

 logist, inasmuch as the organisation of these members must 

 obviously be in strict relation with the localities they inhabit. 

 To account for the distribution of the feathered tribes, and to 

 explain the relationships that exist between them and other 

 animals, a great variety of ingenious theories have been 

 broached, all of them more or less fanciful. The different 

 families, sub-families, and minor groups into which they have 

 been divided have been again and again sorted, like a pack of 

 cards, frequently more in accordance with the whim of the 

 player than with the established rules of the game. And yet a 

 little reflection will show that the great principles of zoological 

 classification are so simple, and at the same time so immutable, 

 that we sometimes cannot but admire the ingenuity displayed in 

 going wrong. 



Few things are more manifest to the student of nature than 

 that, in the distribution of the animal creation, it has been 

 ordained that every locality shall be peopled by forms of life 

 pre-eminently adapted for its occupation. If, therefore, we are 

 asked whether birds ought to be arranged in circles or in 

 squares, in hexagons or in pentagons, in groups of five or in 

 groups of seven, our simple reply would be by inquiring how 

 many localities could be pointed out as requiring appropriate 

 occupants, and to this question it is not difficult to find a satis- 

 factory answer. 



The earth, the water, and the air, throughout their broad 

 domains, must each of them be provided with inhabitants pecu- 

 liarly constructed to live in their diversified regions. Upon the 

 earth, we find the level ground, the mountain, and the glen ; we 

 Fig. 10.— tongue of the woodpecker, find the pathless forests, and the solitary trees and shrubs, and 



bushy underwood. We cast our eyes upon the waters, and we 

 see the world of ocean covering two-third parts of this great 

 a, harpoon-like Tip of the Tongue : d, ,, /, g, k, Hobe, stretching from pole to pole, rolling its mighty waves 



Framework of the Throat ; i, i, Glands fur- 5 ' & l f > & b J 



nishing adhesive secretion. through every zone ; we see the creeks and shallow bays that 



margin it all round, and watch the waves as they approach the 

 shore and lay them down to sleep upon the beach. There are the rivers, too, and lakes, and swamps 

 and marshes which are neither land nor water, sometimes overspread with floating vegetation, some- 

 times a broad expanse of ooze and rushes far too soft to bear the weight of creatures that might try 

 to walk upon the treacherous surface. We look into the air, and there we find between the earth and 

 sky abundant room for birds of every wing. If, therefore, with this little map of the world before us, 

 we reply to the question propounded above, we should be tempted to say that there must necessarily 



SHOWING THE MECHANISM EMPLOYED FOR 

 ITS PROTRUSION. 



