390 



ZOOLOGY 



SECT. 



cavity, sending off an orbital process (orb. jpr.) from its anterior mar- 

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

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

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



The palatines (pi, 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 (pt. } PTG). 

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

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

 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 (ar., ART.), and four investing bones, the angular (an., 



ANG-.), supra-angular (s.an., S.ANG.), 

 dentary (d., I>NT.), and splenial 

 (SPL.), all having the same general 



hh i relations as in the Lizard. The 



ky oid-apparatus (Fig. 1032), is of 

 characteristic form, having an arrow- 

 shaped body (b. ky.) with a short pair 



b.br.z 



s.sl :_ ..._ 



c br 



st 



e.st. 



i. sb. 



e/b.br 



FIG. 1033. Columba livia. The colurnclla auris 

 (magnified). The cartilaginous parts are dotted. 

 e. st. extra-stapedial ; i. st. infra-stapedial ; s. st. 

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

 Zootomy.) 



FIG. 1032. Columba livia. Hyoid 

 apparatus. The cartilaginous parts 

 are dotted, b. br. 1, basi-branchials ; 

 b.hy. basi-hyal ; c.br. cerato-branchial; 

 c. hy. hyoid cornu ; ep. br. epi- 

 branchiaL 



of anterior cornua (c. ky.) derived 

 from the hyoid arch, and a long 

 pair of posterior cornua (c.br., ep.br.) 

 from the first branchial. The 

 columella (Fig. 1033) is a rod- 

 shaped bone ankylosed to the stapes, 

 and bearing at its outer end a three- 

 rayed cartilage or extra-columella (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 upwards, forwards, and outwards. The dorsal end of 

 each is produced into an acro-coracoid process (acr. cor.), and below 

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

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

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



