246 



AYES. 



and the base of the beak which is covered by the cere (ceroma) is the 

 lore. The form and development of the beak vary extremely 

 according to the special mode of subsistence (fig. 655). 



The tongue, which is always movable, lies on the floor of the 



FIG. 655. Forms of beaks (a, b, c, d, lc, after Naumann; g, i, m, o, r&gne animal; Z, f rom 

 Brehm). a t Phcenicopterus ant iquorum ; b, Plafalea leucorodia ; c, Emberiza citrinella ; d t 

 Turdus cyanus ; e, Falco candicans ; f, Mergus merganser ; g, Pelecanus perspicillatut ; h, 

 Mecurvirostra avocetta ; i, JRhynchops nigra; k, Columba livia ; l t BaltBiiiceps rex; m, Ana- 

 stomos coromandelianus ; n, Pteroglossus discolor; o, Mycteria senegalensig ; p, Falcinellus 

 igneus ; q, Cypselus apu. 



buccal cavity. It consists of the horny or fleshy covering of two 

 cartilages attached to the anterior end of the hyoid bone, and serves 

 for deglutition, and frequently for seizing food. The buccal cavity, 

 which in the Pelicans is dilated into a large cervical sac supported 

 by the rami of the lower jaw, receives the secretion of a number of 



