BONES OF THE HEAD. 49 



satisfaction to the reader than is likely to result 

 from a more lengthened verbal disquisition.* 



In regard to the texture of the bones of fishes, 

 their skeletons are either bony, fibro-cartilaginous, 

 or truly cartilaginous. These distinctive appella- 

 tions must be borne in mind by whoever studies 

 in books the natural history of fishes, as the 

 great primary divisions of the subject are based 

 upon the characters which the above terms indicate. 

 The species distinguished by the last named cha- 

 racter are the chondropterygian group, such as 

 sturgeons, sharks, and rays, all of which exhibit 



* Enumeration of the principal bones of the head, with reference 

 to the figures in the preceding cut. 



Cranium. Palatal arch, temporal boties, <|-c. 



1. Principal Frontal. 22. Palatal. 



2. Anterior Frontal. 23. Temporal. 



3. Ethmoidal. 24. Transverse. 



4. Posterior Frontal. 25. Internal pterogoid. 



5. (Basilary.) 26. Jugal. 



6. Sphenoid. 27. Tympanal. 



7. Parietal. 



10. Occipital lateral. 28. Opercle. 



11. Great ala, or temporal ala. 29. (Styloid.) 



12. Mastoidean. 30. Pre-opercle. 



13. (Rupes.) 31. Sympletic. 



14. Orbitaryala. 32. Sub-opercle. 



15. Anterior sphenoid. 33. Inter-opercle. 



16. Vomer. 



Lower-Jaw. 

 Upper-Jaw. u Denta] 



17. Intermaxillary. 35. Articular. 



18. Maxillary. 36. Angular. 



(37.n 



OQ 



Nasal, suborbitary, and supra-tem- og " i 



poral bones. 40 * \ Hyoid and lingual bones. 



19. (First suborbitary.) 4l! 



20. Nasal. 42. J 



21. Supra- temporal. 43. Branchiostegous rays. 



