416 



ZOOLOGY 



SECT. 



ma- 



f.o 



oc.c 



Fi. 1077. Anas boschas( Duck). Ventral 

 view of Skull, a. p. /. anterior palatine 

 foramen ; b. o. basi-occipital ; b. py. basi- 

 pterygoid process ; b. s. basi-sphenoid ; b. t. 

 basi-temporal ; e. o. ex-occipital ; eu. aper- 

 ture of Eustachian tube ; /. m. foramen 

 magnum ; i. c. internal carotid foramen ; 

 3. jugal ; mx. maxilla ; mx. p. maxillo- 

 palatine process ; oc. c. occipital condyle ; 

 pl. palatine ; p. n. posterior nares ; px, 

 premaxilla ; q. quadrate : qj. quadrato- 

 jugal ; v. vomer ; IX, X, foramen for 

 ninth and tenth nerves ; XII, for twelfth 

 nerve. (From Wiedersheim's Vertebmta.) 



girdle furnishes one of the most 

 between Ratitae and 

 Carinatse, but, as 

 with the sternum, 

 the differences are 

 adaptive and not of 

 phylogenetic signifi- 

 cance. In most Cari- 

 natas both coracoid 

 and scapula are large 

 and united with one 

 another by ligament ; 

 the coracoid has an 

 acrocoracoid and the 



and the palatines are articulated 

 in front with the premaxilla, and 

 together push it upwards ; in 

 this way depression of the lower 

 produces an automatic raising of 

 the upper jaw. The great size 

 and strength of both premaxilla 

 and mandible are remarkable, as 

 also is the fact that the orbit is 

 completely surrounded by bone, 

 a backward process of the lacry- 

 mal being joined beneath it by a 

 forward process of the frontal. 



The mandible contains in the 

 young Bird the six bones on each 

 side characteristic of Reptiles ; 

 the coronary is, however, often 

 absent. As a rule the head of 

 the quadrate articulates with the 

 roof of the tympanic cavity by 

 a single facet in Ratitae, by a 

 double facet in Carinata3. The 

 Tiyoid always agrees in essential 

 respects with that of the Pigeon ; 

 in the Woodpecker the posterior 

 cornua are curved round the 

 head and attached to the skull in 

 the neighbourhood of the right 

 nostril, a very flexible and pro- 

 trusible tongue being produced. 



The structure of the shoulder- 

 fundamental distinctive characters 



scapula an acromion 

 process ; the coraco- 



Fia. 1078. Skull of Ara (Macaw). (From a photograph by 

 A. Hamilton.) 



