72 COMPARATIVE ANATOMY 



8. Splenial. 

 y. Angular. 



10. Supra-angular. 



11. Coronoid. 



12. Palatine. 



13. Pterygoid. 



II. Investing Bones of the Outer Surface (enumerated 

 from before backwards). 



1. Nasal. 



2. Lachrymal. 



3. Frontal. 



4. Prefrontal (of Reptiles). 



5. Postfrontal or postorbital. 



6. Supraorbital. 



7. Parietal. 



8. Temporal or squamosal. 



9. Supraoccipital (in part). 



III. " Cartilage Bones." 



i, Basioccipital | p^.g^g^^j, ^^jy -^ Amniota (forming the base 

 Z. ^asispnenoid v- ^^ ^^^ ^^ 



3. Presphenoid ) ' 



4. Exoccipital (and supraoccipital, in part). 



5. Pro-, epi-, and opisthotic, also (in Teleostei) sphenotic and 



pterotic (forming the bony auditory capsule). 



J .I. j- sphenoid, developed in the trabecular region. 



8. Ethmoid, together with the rest of the skeleton of the nose 



(turbinals, &c.). 



9. Quadrate. 



10. Articular. 



11. Visceral skeleton (in part). 



Anatomy of the Skull. 



Special Pabt. 



A. Fishes. 1 



In the Cyclostomata, the skull is developed essentially in the 

 manner already described. Later, however, it shows many special 

 peculiarities, probably in consequence of the suctorial (Petromyzon) 



1 In Amphioxus (Acranla) there is no cranial skeleton, and the elastic non- 

 cartilaginous rods which support tlie branchial apparatus are not comparable with 

 the visceral skeleton of the Craniata. 



