CHAPTER XVIII. 



Genus HjEMATOPUS. 



Diagnosis, 

 of genus. 



CHARADRiiNiE rostro recto : tarso reticulato, quam rostrum breviore. 



Generic 

 characters. 



The Oystercatchers are a small compact group of birds, very closely connected with each 

 other, and very clearly differentiated from all other groups of birds. 



In the subfamily of Charadriines the scutellations of the tarsus vary to a remarkable 

 degree. In some species the tarsus is covered both in front and at the back with 

 broad scutellations, the front row being connected with the back row by fine reticulations 

 which cover the side of the tarsus. In other species the front row of scutellated plates 

 alone is present, the back of the tarsus as well as the sides being covered with fine reticu- 

 lations ; whilst in a third group the fine reticulations extend ail round the tarsus. These 

 three groups are obviously artificial, and are not separated from each other by a hard- 

 and-fast line ; but many genera include forms which are intermediate between one and the 

 other. Nothing of this kind, however, occurs in the Oystercatchers ; they all clearly and 

 undoubtedly belong to the third category, in which the whole of the tarsus is covered by 

 a fine network of small hexagonal reticulations. To this group belong also the Ibis-billed 

 Oystercatcher {Ibidorhynchus), the Stone-Curlews {(Edicnemus), the Stilts and Avocets 

 (Himantojms), and some of the Plovers (C/iaradrius). To distinguish the genus Hcematojws 

 from these genera it is necessary to take into consideration two other characters. Com- 

 pared with the Stilts, Stone-Curlews, and Plovers, the Oystercatchers have long bills and 

 short legs, so that the character of bill longer than tarsus effectually excludes these birds. 

 It does not, however, exclude some of the Avocets, with their slender recurved bills, or the 

 Ibis-billed Oystercatcher, with a bill decurved like that of a Curlew. The clumsy, nearly 

 straight bill of the Oystercatchers distinguishes them from these birds. In spite, however, 

 of the extraordinary fact that it possesses a bill of such a totally different shape from that 

 of Oystercatchers, there can be no doubt that the Ibis-billed Oystercatcher is their 

 nearest surviving relative ; it is, in fact, nothing but an Oystercatcher with a modified 

 bill. The bill of the Oystercatchers is very abnormal. Most birds have beautiful bills, 



