390 



ZOOLOGY 



SECT. 



cavity, sending off an orhital i^rocess {orb. pr.) from its anterior mar- 

 gin, and presenting below a condyle for articulation with tlie man- 

 dible; it is freely movable upon its tympanic articulation, so that 

 the lower jaw has a double joint as in Lizards and iSnakes. 



The palatines (^;/, PAL.) have their slender anterior ends anky- 

 losed with the maxilla, their scroll-like posterior ends articulating 

 with the pterygoids and the rostrum. The pterygoids {jit., PTG). 

 are rod-shaped and set obliquely ; each articulates behind with the 

 quadrate, and, at about the middle of its length, with the hasi- 

 pterygoid process, a small facetted projection of the base of the 

 rostrum. There is no vomer in the Pigeon. 



The mandible of the young Bird consists of a replacing bone, the 

 articular {or., ART.), and four investing bones, the angular {an., 



ANG.), supra-angular (s.an.,S.AA'G.), 

 dentary (d., DNT.), and splenial 

 {SPL.), all having the same general 

 relations as in the Lizard. The 

 liyuid-appa rains (Fig. 1032), is of 

 .^ f characteristic form, having an arrow- 



shaped body (h. hy.) with a short pair 



b.brz 



s.itl- 



c br 



st- 



— ephr- 



i.st. 



Fig. 1033.— Columba livia. The columella aurls 

 (magnified). 'J'hc caitilaginous parts are dotted. 

 e. St. extra-stapedial ; (. st. infra-stai")cdial ; «. si. 

 supra-stapedial ; st. stapes. (From Parker's 

 Zootomy/.) 



Fir;. 10.3-2.— Columba livia. Hyoid 



apparatus. 'I'lie cartilaginous parts 

 are dotted. '). In: ], )>asi-l>ranc-hials ; 

 O.liy. basi-hyal ; cln: ccrato-branehial; 

 c. hy. hj-oid cornu ; tji. In: ei^i- 

 branchial. 



of anterior cornua (r. hy.) derived 

 from the hyoid arch, and a long 

 pair of posterior cornua (c.br., cp.hr.) 

 from the first branchial. Tiie 

 (■ohtmcVa (Fig. lOSS) is a rod- 

 shaped bone ankylosed to the stapes, 

 and bearing at its outer end a three- 

 rayed cartilage or cxtra-columclla (e.st , i.st., s.st.) fixed to the 

 tympanic membrane. 



The shoulder -girdle (Fig. 1027) is quite unlike that of other 

 Craniates. There is a pair of stout, pillar-like coracoids (cor.) 

 articulating with deep facets on the anterior border of the sternum, 

 and directed ujnvards, forwards, and outwards. The dorsal end of 

 each is produced into an arro-curaroid. jirocess (acr. cor.), and below 

 this, to the posterior aspect of the bone, is attached by ligament a 

 sabrc-shaped scapula (scp.) which extends backwards over the ribs, 

 and includes, with the coracoid, an acute angle, the coraco-scapular 



