474 THE SHOVELLER. 



Some 20.00 long and 30.00 in extent, most of the plumage 

 is finely barred with black and white, giving a general 

 gray effect; middle wing coverts, chestnut ; greater ones, 

 black; speculum, white. The species may always be differ- 

 entiated by the wing. 



THE SHOVELLER. 



A highly specialized form, in nature, is a Duck's bill; and 

 so completely do form and function correspond therein, that 

 it may be impossible to conceive of adaptation more per- 

 fect. The head, or the entire body, being immersed in the 

 act of feeding, and that often to a great depth, or in turbid 

 water, the food, which itself is often found in the mud, 

 must be selected in great part, at least, without the aid of 

 sight; the sensibilities of touch and taste, therefore, are 

 particularly requisite. To render these faculties of percep- 

 tion as acute as possible, the soft, fleshy tongue, the carne- 

 ous interior of the mouth in general, and the soft, sensitive 

 exterior of the bill are well supplied with a complicated 

 system of nerves, thus enabling the bird to detect its food 

 by the sense of feeling, and probably even by the sense of 

 taste. The broad bill, with its finely lamellate edges, serves 

 as a sort of sieve or strainer, to retain the proper articles of 

 diet, while the foreign or extraneous matter is allowed to 

 escape ; the Duck thus feeding somewhat after the manner 

 of the Baleen or Right Whale. Though constructed on the 

 same general plan, the bills of the various species of Ducks 

 include a great variety of patterns. Some, as those of the 

 Old Wives and the Pintails, are quite small, whereas, 

 in many of the river Ducks, the bills are large and broad. 

 The most exaggerated, both in size and form, is that of the 

 rather small river Duck called the Shoveller {^Spatula dypeatd). 

 Though but little larger than a Teal, its bill is quite a little 



