350 



THE FROG. PHYLUM CHORDATA 



BACKBONE 



In the backbone there are nine vertebrae and a long bone, 

 known as the urostyle which represents several vertebrae fused 

 together. Each vertebra has the same general parts as those of 



m.A 



Fig. 265. — Skeleton of frog. The half of the pectoral girdle, and fore- and hind- 

 limb of the right side, are not shown. 



pmx., Premaxilla ; mx., maxilla ; n., nasal ; sph., sphenethmoid ; p.f., fronto-parietal ; P.O., Pro-otic ; 

 pt., pterygoid: q.j., quadratojugal ; sq., squamosal; Q., quadrate; c, columella auns; A., atlas; 

 t.p., transverse process; S.V., sacral vertebra; U., urostyle; S.sc, suprascapula ; //.humerus- 

 R.U., radio-ulna ; Cp., carpals ; Mc, metacarpals ; //., ilium ; 7s., ischium ; F., femur; !.!•., tibic 

 fibula -.Ca., calcaneum ; As., astragalus ; C, calcar ; ML metatarsals. 



