SKULL 



93 



A 



' /,''-" ^f*y,'~ 

 , ' *^zz-- I 



- / / f fe- ^r 



p'roo'f flsjvh alsjtli 



N.olf orl.sph ' 



socc . / 



enioT 



* i 



B 



mf. eocene 



-Col.verf 



I a son 



Of!C 



FIG. 70. A. CRANIAL SKELETON OF SALMON AFTER REMOVAL OF THE JAWS 

 AND ORBITAL AND OPERCULAR BONES. From the right side. 



B. The same in longitudinal section. The cartilaginous parts are dotted in 



both figures. 



alsph, alisphenoid ; basocc, basioccipital ; basph, basisphenoid ; Col. vert, point 

 of connection of the skull with the vertebral column ; ekteth, ectoethmoid ; 

 epiof, epiotic ; exocc, exoccipital ; fr, frontal ; N.olf, canal for the olfactory 

 nerve ; opiafh, opisthotic ; orbsph, orbitosphenoid ; pfero, pterotic (squamosal) ; 

 prool, prootic ; jwph, parasphenoid ; socc, supraoccipital ; sy>hot, sphenotic ; 

 co, vomer. 



an ossified zone, the anterior and posterior parts of which are 

 usually known respectively as the orbitosphenoid and alisphenoid. 

 On the base of the skull is a basisphenoid, ventrally to which 

 is a parasphenoid, developed in the mucous membrane of the 

 mouth. More anteriorly is a vomer, and laterally the palato- 



