34 BILL 



unpaired piece being more or less separated from the lateral 

 pieces. In the majority of birds the horny covering forms one 

 coherent sheath. 



Frequently the edges of the mandibles and of the maxillae are 

 serrated to secure a firmer hold upon the food, for instance in 

 Toucans. In the Anseres these tooth-like serrations are arranged in 

 the shape of numerous transverse lamellse, and hence the name 

 " Lamellirostres, ' which, especially in the Shoveler, form an elaborate 

 sifting apparatus. 



The bill of the Flamingos is likewise furnished with such sifting 

 lamellse ; the two halves of the under jaw are considerably enlarged, 

 so that the comparatively narrow upper jaw closes upon a wide 

 cavity. In addition to this the whole bill is bent downwards, 

 in some species rather abruptly ; these long-necked birds being thus 

 enabled to sift the soft mud of lagoons with their bill in an inverted 

 position, the dorsal surface of the bill being turned towards the 

 bottom. Undoubtedly this most peculiar bill is a secondarily 

 acquired character, referable to the mode of feeding, which again 

 is connected with the long neck and legs. This view is 

 strengthened by the fact that very young Flamingos still have 

 straight and short bills, which very gradually and only compara- 

 tively late assume the final shape. 



Fine sifting lamellse occur also in Prion (Whalebird), and as a 

 dense brushlike mass on the inside of the premaxillary region in 

 Anastomus. The jaws of this genus have the further peculiarity 

 that they do not shut completely, being slightly curved in opposite 

 directions. u 



In the Spoonbilled Sandpiper, Eurmorhynchus pygmseus, the 

 end of the upper and lower bill is of a peculiar spatulate and heart- 

 shaped form. 



The broad and flattened spatulate bill of the SPOONBILLS, the 

 boat or shoe-shaped bill of the Whale-headed Stork, Balxniceps, and 

 of the Cancroma (Boatbill), the long bills of the Ibis and the 

 Whimbrel, curved downwards, and upwards in the Avoset, need no 

 further comment but that they all are illustrations of the adapta- 

 tion to a special mode of life, and therefore not necessarily indica- 

 tive of relationship, as rather analogous than homologous structures. 



The beak of Parrots is extremely strong, and well adapted 

 to the breaking open of nuts by sheer force. The mandible ends 

 in a transverse blunt edge, which presses against a corresponding 

 horny prominence of the upper beak. In the large Microglossa 

 (Cockatoo), which lives on the stone-hard fruit of the kanari-tree 

 (Canarium commune), the beak bears a striking resemblance to a 

 sledge-hammer. Transverse ridges, like those of a file, are common 

 in front of the prominence of the upper jaw, the bird using them 

 as a rasp — no Parrot s"\vallowing anything but absolutely com- 



