GALLINACEOUS BIRDS. 



547 



rubbish, forming a hot-bed, in which its eggs are left to 

 hatch. The raegapods, together with the American guans 

 and curassows (CracidcB), form a sort of passage from the 

 gallinaceous to the columbine birds. One of the most puz- 

 zling forms for the systematic ornithologist to deal with is 

 the hoasin of Guiana ( Opisthocomus cristatus Illiger). In 

 this bird the keel of the breast-bone is 

 cut away in front, the wish-bone unites 

 with the coracoid bones, and also with 

 the manubrium of the breast-bone, a 

 thing of rare occurrence (Coues). 



In the tinamous of Central and South 

 America the tail-feathers are, in some 

 cases, entirely wanting, and the breast- 

 bone and skull-bones have some anom- 

 alous features. Most all gallinaceous 

 birds have plump 

 bodies, with short 

 beaks and small 

 rounded wings, not 

 being good fliers. 

 In some of their 

 cranial characters | 

 they are so peculiar 

 that Huxley makes 

 them one of his 

 primary divisions 

 of CarinatcB. 



We now come to 

 birds of a higher 



,. , ,v Fig- 472. White-tailed Ptarmigan (Layopits leucurus), 

 type, in WniCll tlie in (upper figure) summer and (lower figure) winter 



knee and part of pl " 



the thigh are free from the body, the leg being usually 

 feathered down to the tibio-tarsal joint ; the toes are usually 

 on the same level, being fitted for grasping or perching. 



The doves are rapid fliers, but a notable exception is seen 

 in their extinct ally the Dodo (Didus ineptus Linn.) of 

 Mauritius, which became extinct on the island of Mauritius 

 in the seventeenth century, while the solitaire. Didus (Pc- 



