PLOVEKS. 49 



Order XII. CHAEADRIIEORMES. Plover-tribe. 



The birds included in this Order present great variety in size, shape, &f^^ 

 and coloration, and it is interesting to notice that these differences are 

 generally traceable to peculiar methods of feeding. Though a few 

 species frequent arid plains, they are essentially birds of the fen and of 

 the sea-shore, or haunt the banks of streams and desolate marshes,feeding 

 on worms, small shell-fish, and Crustacea, For the capture of these the 

 beak and legs have become modified in many ways. A considerable 

 number of species exhibit conspicuous changes in the coloration of the 

 plumage, adopting a distinct summer and winter dress ; others undergo 

 but little seasonal change. The richly coloured eggs do not ordinarily 

 exceed four in number, and are deposited in a slight hollow in the 

 ground with little or no preparation in the form of a nest. The young 

 are quite active when hatched and clothed in a thick covering of 

 beautifully patterned down, the colour of which is more or less deter- 

 mined by the surroundings amid which they are hatched. 



Family I. Dromadid^. Crab-plovers. 



On the floor of this Case, on the right-hand side, we find the sole fCaae 27.1 

 representative of this very aberrant and remarkable family, which 

 inhabits the coast-land and sandy islands of India, Arabia, and East 

 Africa. The nesting habits differ entirely from those of every other 

 member of this order, for the Crab-plover {Dromas ardeola) (463) 

 breeds in deep burrows excavated in the sand-hills and lays a single 

 large white egg. The young are covered with greyish down and, like 

 young petrels, remain in the burrows dui'ing the day. 



Family II. Chionidid^. Sheathbills. 



The Sheathbills, of which three species are known, form another very [Case 27.] 

 aberrant family, inhabiting the islands adjacent to the southern extre- 

 mity of South America and in the South Atlantic Ocean. The base 

 of the bill is covered with a saddle-shaped horny sheath, the cheeks are 

 naked, covered with wattles in Chionis alba (464), and the wings are 

 armed with spurs. The habits of the Lesser Sheathbill [Chionarchus 

 minor) (465) are described as resembling in some respects those of 

 pigeons, while in their gait and flight they closely resemble Ptarmigan. 

 The rough nest of dried plant-stems is made in a hollow among the 

 rocks or occasionally in a Petrel's burrow, and contains two or three 

 eggs thickly spotted and mottled with purplish-red. 



