72 



General Biology 



Pro. /./>. /•'. 



Fig. 20. The Axial Skeleton of the Frog. 



A. The skull and vertebral column of frog viewed from dorsal surface. 



B. The same from the ventral surface. 



C. Lateral view of the urostyle; a bristle is passed through the foramen for 

 the tenth spinal nerve. 



D. The branchial skeleton of the frog: O., orbital fossa; pmx., premaxilla; 

 mx., maxilla; q-j., quadrato-jugal; na., nasal; pf., parieto-frontal; c, exoccipital; 

 fm., foramen magnum; pro., prootic; sq., squamosal; sp.et., sphenethmoid; par., 

 parasphenoid; pal., palatine; vo., vomer; ptg., pterygoid; av., atlas; c, centrum; 

 ar., neural arch; zyg., zygapophysis ; trv., transverse process; ur., urostyle; H., 

 body of hyoid; Ha., anterior cornu; H.p., posterior cornu of hyoid. 



E. The skull of a frog, seen from the right side: a.c, Anterior cornu of hyoid; 

 a.sp., angulo-splenial; b., body of hyoid; col., columella; d., dentary; c.n., external 

 nasal opening; f.p., fronto-parietal; m., maxilla; mm., mentomeckelian; n., nasal; 

 o.c, occiptal condyle; p.c, posterior cornu of hyoid; p.m., premaxilla; pro., prootic; 

 pt., pterygoid; q., quadrate; q.j., quadratojugal; sp., sphenethmoid; sq., squamosal. 



F. The skull of a frog seen from behind: col., Columella; ex., exoccipital; 

 f.m., foramen magnum; o.c, occipital condyle; pro., prootic; pt., pterygoid; q., 

 quadrate; q.j., quadratojugal; sq., squamosal; IX. X., foramen for ninth and tenth 

 cranial nerves. 



G. The cartilaginous skull of a frog, seen from above after the removal of 

 most of the bones: a.f., Anterior fontanelle; au., auditory capsule; cr., cranium; 

 ex., exoccipital; l.p.f., left posterior fontanelle; nas., nasal capsule; o.c, occipital 

 condyle; pro., prootic; pt., pterygoid; q., quadrate; q.j., quadratojugal; sp., 

 sphenethmoid; u.j., upper jaw bar. 



