646 



CYGNINJE. 



SWANS AND ALLIED SPECIES. 



The small group of very large birds commonly known 

 by the name of Swans presents forms intermediate between 

 those of the Anserinse and Anatinae, although to the ordinary 

 observer they seem much more allied to the former than to 

 the latter. 



They have the body of an elongated, somewhat elliptical 

 form ; the neck very long ; the head of moderate size, oblong, 

 compressed, flattened in front; the bill rather longer than 

 the head, high at the base, depressed toward the end, of 

 nearly equal breadth throughout, and rounded at the end ; 

 the upper mandible internally concave, with a middle row of 

 prominent blunt tubercles, a row of flattened tubercles, and 

 a row of slender, little elevated lamellae on each side. The 

 tongue is fleshy, thick, with the edges thin, fringed with 

 slender, flattened papilla?, under which is a smaller row of 

 filaments. The oesophagus is narrow, a little dilated at the 

 lower part of the neck ; the stomach transversely elliptical, 

 extremely muscular ; the intestine long, rather narrow, with 

 long cylindrical coeca. The trachea has the inferior larynx 

 laterally compressed. 



The eyes are small : the nostrils elliptical, medial. The 

 legs, placed a little behind the centre of equilibrium, are 

 short, stout, with the tibia bare for a short space ; the tarsus 

 considerably compressed ; the toes four, the first very small 

 and free, the anterior longer than the tarsus, the outer a 

 little shorter than the third ; the webs full ; the claws strong, 

 arched, compressed, rather obtuse. 



The plumage of the head and neck is soft and blended, 

 of the other parts full, close, and firm. The wings very 



