THE SKELETAL SYSTEM 



163 



SUPRAOCCIPITAU 

 BASIOCCIPITAU 

 HYOMANDIBULARs 

 SQUAMOSALS 



1ST VERTEBRA 



NEURAL SPINE 



PARIETAL- 

 PARASPHENOID 

 PTERYGOIDS*. 

 FRONTAL--^^-^^ 

 ECTETHMO ID-^!:2M^^2^:^^ 

 MESETHMOID "^ " 



NASAL- 

 PALATINE 



■OPERCULAR 

 -PREOPERCULAR 

 SUBOPERCULAR 

 SYMPLECTIC 



QUADRATE 

 ;<i- -I NTEROPERCUL AR 



Fig. 154. — Skull of hake in left lateral aspect. Membrane bones are cross-hatched, 

 pro-cartilage bones stippled. Compared with the skull of ganoids, that of teleosts 

 shows an increasing dominance of inembrane bones over those preformed in cartilage. 



Fig. 155. — Dorsal and ventral views of the skull of turtle, Trionyx. Compared 

 with the skull of the bony fish, that of reptiles shows increased compactness and integra- 

 tion of elements, bo, basioccipital; bs, basisphenoid; eo, es, exoccipital; /, frontal; j, 

 zygomatic (jugal) ; m, mx, maxilla; n, prefrontal; opis, opisthotic; p, (behind orbit) 

 postfrontal, (others) parietal; pal, palatine; pmx, premaxilla; pno, prootic; pt, pterygoid; 

 q, quadrate; s, supraoccipital; v, vomer. (From Kingsley's "Comparative Anatomy of 

 Vertebrates.") 



