234 AN ELEMENTARY TEXT-BOOK OF BIOLOGY. 



tenth, and eleventh (IX. and X.), while the twelfth passes out 

 by a small condylar foramen situated in the ex-occipital near the 

 condyle (XII.) 



The facial part of the skull consists of the nasal capsules and 

 jaws. The nasal capsules contain a good deal of cartilage, and 

 are separated by a cartilaginous nasal septum, which is a con- 

 tinuation of the mesethmoid. A scroll-like fold, the turbinal, 

 projects from it on either side. Below this is a slender vomer, 

 just in front of the basi-sphenoidal rostrum. The capsules are 

 partly roofed in by the nasals, which unite with the frontals 

 behind, and are deeply notched in front. The notches partly 

 bound the external nares. 



The margin of the upper jaw is formed in front by the pre- 

 maxillce, each of which unites behind with a delicate rod-like 

 maxilla, from the anterior end of which a flat maxillo-palat'me 

 process projects towards the middle line. The maxilla fuses 

 behind with a styliform jugal. These two last bones form the 

 greater part of a sub-orbital bar, which is completed posteriorly 

 by a guadrato-jugal, the rounded posterior end of which is united 

 by a fibrous band with the quadrate, a short thickened bone, 



Fig. 68. ENDOSKELETOX OF PIGEON (Cartilage dotted). A and A', Skull, 

 side and under views; s-oc, supra-occipital; ex-oc, ex-occipital; b-oc, 

 basi- occipital ; c, condyle ; pa, parietal ; sq, squamosal ; a-s, ali-spheuoid ; 

 fr, frontal; fr', orbital process of ditto; i-o.s, inter-orbital septum; 

 la, lachrymal; b-t, basi-temporal ; p-s, para-sphenoid; v, vomer; na, 

 nasal ; p-mx, pre-maxilla ; mx, maxilla ; mx-p, maxillo-palatine process ; 

 j, jugal ; q-j, quadrato-jugal ; pi, palatine ; pt, pterygoid ; qd, quadrate ; 

 d, dentary; ar, articular ; an, angular; s-an, supra-angular; ly, tympanic 

 cavity (reference line runs to fenestra ovalis); Eu, Eustachian opening; 

 f-m, foramen magnum. I., II., &c. , Nerve exits. (V., just above for- 

 amen for fifth.) B, Left columella, enlarged; pi, plate fitting into 

 fenestra ovalis. C, Hyoid apparatus, from above ; g-hy, glosso-hyal ; 

 b-ky, basi hyal; b-br, basi-branchial; a.c, anterior cornua; p.c, posterior 

 cornua. D and D', "Sacrum" and pelvis, under and side views, num- 

 bers refer to vertebras ; t, thoracic ; /, lumbar ; S, sacral ; c, caudal ; 

 c', free caudal; p-sh, plough-share bone; r, rib; il, ilium; pb, pubis; 

 is, ischium ; ac, acetabulum ; ant, anti-trochanter ; ob, obturator 

 fissure; i-s.f, ilio-sciatic foramen. E, 1-6, Vertebrae. 1, Atlas: 2, axis: 

 3, two free cervical, from above : 4, ditto, from side : 5, ditto, from 

 front: 6, first thoracic ; c, centrum; n.sp, neural spine; t.p, transverse 

 process ; hy, hypapophysis ; a-z, pre-zygapophyses ; p-z, post-zyga- 

 pophyses; o.p, odontoid peg; i.l, cervical rib; n.c, neural canal; r.c, 

 vertebrarterial canal ; r, vertebral rib ; c.p, head ; tb, tubercle ; un t 

 uncinate process : 7, sclerotic ring. 



