340 BRITISH BIRDS. 
from those of the nearly allied genera by their short tails, which are never 
longer than the bill. 
This genus may be subdivided into two subgenera, the species of which 
very closely resemble each other in general appearance, but differ in the 
number of their toes—twelve of them having three toes in front, and 
seven of them only two. The general colour of the plumage of the upper 
parts is blue and green with metallic reflections, occasionally crossing the 
breast, and the underparts are generally rich chestnut, but occasionally 
white. The wings are short, concave, and rounded, and the tail is very. 
short and rounded. 
The birds in this genus are found throughout the Old World except the 
Arctic regions and New Zealand. ‘They number about twenty species, 
only one of which is European and is a resident in the British Islands. 
The birds belonging to this genus frequent almost exclusively the imme- 
diate neighbourhood of streams and lakes, into the waters of which they 
plunge to secure their food, which consists principally of small fish and 
water-insects. Their flight is straight and quick, their wings beating 
with great rapidity. They breed in holes in banks, which they generally 
excavate themselves, and make no nest. Their eggs are very round, pure 
white, and very highly polished. 
