54 A HISTORY OF BIRDS 



plovers {Thinocoridce) and Jacanas (JParridce), Crab-plovers 

 {DromadidcB), "Sheath-bills" {Chionididcs) and the Gulls and 

 Auks {Laridce and Alcidcs). With the exception of the Stone- 

 curlews and the Gulls and Auks, these more ancient types 

 are not generally very well known, save to the expert. 



The Stone-curlews, by all the older Ornithologists, were re- 

 corded as closely allied to the Bustards, some of the smaller 

 species of which they approach not only in size but also in 

 their general coloration, and in the shortness of the toes. 

 Nevertheless, there can be no question but that they are to be 

 regarded as Plovers, in a wide sense, and not as members of the 

 Gruiformes. The likeness which they bear to the Bustards is ' 

 due in part to convergence, to the moulding influence of a like 

 environment — dry heaths and wastes — and in part to their 

 common origin. The Pratincoles are certainly not very Plover- 

 like in their general appearance, indeed they have been as- 

 sociated more than once with the Night-jars, and even with 

 the Swallows ! As might be supposed, they bear a superficial 

 likeness to the Swallows on account of the length and shape 

 of their wings ; but a very cursory examination is sufficient to 

 show their Pluvialine affinity. Nearly allied to these birds are 

 the long-legged "Coursers" {Cursorius) of Europe, Africa and 

 tropical Asia, one species indeed occurring as an occasional 

 visitant to the shores of Great Britain. 



The " Seed-plovers " or " Seed-snipes " of South America 

 are no less un-plover like in their general appearance. Indeed 

 from their general appearance they might well pass for some 

 sombre-coloured member of the Fowl tribe, or Sand-grouse. 

 In many of their habits indeed they also recall the Gallinaceous 

 birds, nevertheless they are unquestionably aberrant Plovers. 



The "Jacanas" {Parridcz) again serve as pitfalls to the 

 unwary, inasmuch as superficially they bear a much closer 

 resemblance to Rails ; and this likeness is rendered the more 

 striking on account of the great length of the toes, which is 

 further exaggerated by claws of enormous length. 



Almost as puzzling, at first sight, are the Crab-plovers and 

 Sheath-bills. The former are long-legged, black and white 

 birds with a short, heavy beak. Maritime in habit they occur , 

 commonly along the East Coast of Africa from the Red Sea 

 to Natal, as well as along the northern and western shores of 



