462 STRUCTURE AND CLASSIFICATION OF BIRDS 



blend with the sheath of the carotids, which when pulled 

 upon they compress, as also the jugulars. This may con- 

 ceivably be a provision for increasing the blood supply of the 

 wings by interrupting that of the head. Finally in Gygnus, 

 Mergus, and Sarcidiomis the expansor secundariorum is 

 ciconiiform. 



The deltoid has a strong scapular shp. The ancorimus 



Fig. 221. — Sykinx os B. caryophyllacea S ■ Eight-hand Pig., Pkont 

 View; Left-hand, Side View. (After Garkod.) 



has a humeral slip. In the hind limb all Anseres have the 

 formula ABX-f-. The femorocaudal is slender, the acces- 

 sory very large. In Bizmra lobata the amhiens has a pecu- 

 liarity found also in Phalacrocorax and the extinct Hesper- 

 ornis — that its tendon perforates the patella. The glutaus 

 maximus is very large, and its origin descends below the aceta- 

 bulum. A marked peculiarity of the Anseres, found else- 

 where in Struthio, is that the biceps femoris gives off a slip 

 to the gastrocnemius. In most Anseres the flexor longus 

 hallucis gives off a slip to the hallux before fusing with the 



