66 Vertebrata. 



means of glands in the throat, a glutinous material of 

 which it constructs its nests, which are the edible 

 birds' nests of Eastern commerce, used as food in 

 China. The humming-birds of Brazil, of which there 

 are very numerous species, are also examples of this 

 order, and include the smallest forms of the entire 

 class of birds; thus Mclisuga minimus, from the island 

 of San Domingo, only weighs about nine grains, and 

 measures two inches in extreme length ; its nest is 

 about the size of a walnut, and it contains two eggs 

 each nearly as large as a pea. 



38. Order 5, PercMng birds (?asseres.) This 

 large order includes all our small birds, with the ex- 

 ception of those hitherto mentioned. They may be 

 recognised by possessing short wing coverts, a tarsus 

 FIG. 28. covered in front with seven large 



scales, and slender toes, of which 

 the first joints of the two outer are 

 united. They have a well-deve- 

 loped syrinx or organ of voice, and 

 many of them can sing. These birds 

 are very numerous, and make up 



Foot of passerine bird. , ..... . 



about twenty-one families. The 

 best known of these are the following : The thrushes, 

 known by their slightly curved bill, with a notch or 

 tooth on each side near the tip, and with bristles at 

 the angles of the gape of the mouth. They are 

 insect-eaters for the most part. The commonest 

 species are the song thrush; the blackbird, known 

 by its yellow bill and eyelid-edge and its black 

 body ; the missel thrush, known by its white-tipped 

 three outer tail feathers ; the fieldfare, the redwing. 



