84 DEVELOPMENT OF THE SKELETON OF THE TUATARA. 
PLATE V, 
SPHENODON PUNCTATUS.—THE QUADRATE, HYOID, AND COLUMELLA AURIS. 
an., angular; 6., boundary between stapes and extrastapedial cartilage ; }.a., branchial arch ; 
b.c., branchial cleft ; ¢.!, horizontal semicircular canal ; ca., carotid artery ; ca.’, branch of carotid 
artery; ¢c.au., auditory capsule ; e.c., extrastapedial cartilage ; ew., eustachian recess; fe., fenestra 
in suprastapedial cartilage; h.', anterior cornu of the byoid; j.v., jugular vein; mk., Meckel’s 
cartilage; m¢., mouth; n. v.—ai., cranial nerves ; x. vii.', branch of chorda tympani; ph., pharynx ; 
p-p., parotic process ; pq., pterygoquadrate ; q., quadrate ; g.’, otic process of quadrate; s.a., supra- 
angular ; sq.', anterior process of squamosal; sq.", posterior process of squamosal; s.s¢., supra- 
stapedial cartilage ; s¢., columella (stapes) ; s¢.', boundary between columella and extrastapedial 
cartilage. 
Figs. 1-5. Stage P. A series of sections, in order from within outwards, showing the primary 
relationships of the columella auris to the hyoid and quadrate. x 40. 
Fig. 1. Represents the most internal section No. 1, 
Fig. 2. Represents section No. 6. 
Fig. 3. x mp ING: 
Fig. 4 a; py INi@s IO, 
Bios os ¢ sy NICE Ac 
Fig. 6-11. Stage Q. A similar series to the above. xX 25 
Fig. 6. Represents the most internal section No. 1. 
Fig. 7. Represents section No. 11. 
ions: Fi Pe Nowe: 
Fig. 9. AS » No. 386. 
Fig. 10. % oy NI@b de 
Wee, Wale 5 ase NOS Di 
Fig. 12. Stage R. Transverse section of auditory region passing through quadrate and columella 
auris. xeon 
Figs. 13-14, Stage S. Sections, in the same order as figs. 1-5, showing the relation of the 
suprastapedial cartilage to the quadrate. x 20. 
Fig. 13. Represents the more internal section No. 1. 
Fig. 14. Represents section No. 16. 
