THE SKELETON OF THE FROG. THE SKULL. 159 



process. It is connected behind with the maxilla (figs. 24 and 

 26, 10), a long flattened bone which forms the greater part of 



FIG. 26. A, LATERAL VIEW OF 



CRANIUM OF A COMMON FROG 



1. sphenethmoid. 



2. fronto-parietal. 



3. pterygoid. 



4. squamosal. 



5. tympanic membrane. 



6. exoccipital. 



7. parasphenoid. 



8. pro-otic. 



9. quadratojugal, 



10. maxilla. 



11. nasal. 



12. premaxilla. 



13. anterior nares. 



B 



THE SKULL, B, POSTERIOR VIEW OF THE 



(Rana temporaria) x 2 (after PARKER). 



14. mento-meckelian. 



15. dentary. 



16. angulo-splenial. 



17. basilingual plate. 



19. quadrate. 



20. columella. 



21. occipital condyle. 



22. anterior cornu of the hyoid 



(cerato-hyal). 



23. foramen magnum. 



II. IX. X. foramina for the exit 

 of cranial nerves. 



the margin of the upper jaw, and gives off near its anterior end 

 a short process which projects upwards and meets the nasal. 



Both maxilla and premaxilla are grooved ventrally, and 

 bear, attached to the outer more* prominent margin of the groove, 

 a row of minute conical teeth. These teeth are pleurodont, 

 that is, are ankylosed by their bases and outer sides to the 

 margin of the jaw. Each tooth is a hollow cone, the basal 



