1. supra-occipital. 2. epi-otic. 3. pterotic. 4. sphenotic. 5. frontal. 6. median ethmoid. 7. parietal. 8. nasal. 9. lachrymal. 10. suborbital. 11. supra-orbital. 12. cartilaginous sclerotic. 13. ossification in sclerotic. 14. meso-pterygoid. 15. meta-pterygoid. 16. palatine. 17. jugal. 18. quadrate. 19. maxillae 20. premaxillae. 21. articular. 22. angular. 23. dentary. 24. hyomandibular. 25. symplectic. 26. epi-hyal. 27. cerato-hyal. 28. hypo-hyal. 29. glosso-hyal. 30. opercular. 31. sub-opercular. 32. infra-opercular. 33. pre-opercular. 34. supratemporal. 35. branchiostegal rays. 36. basi-branchiostegal.] In a =ventral view= the cranium is seen to be chiefly covered by two large membrane bones, the _parasphenoid_ (fig. 9, B, 9) behind, the _vomer_ in front. A view of the =posterior end= differs from that of the cartilaginous cranium only in the fact that the end of the _parasphenoid_ appears lying ventral to the basi-occipital. The =lateral view= differs very markedly from that of the cartilaginous cranium, there being a great development of membrane bone in connection with the jaws and branchial apparatus. Lying dorsally are seen the _median ethmoid_, _frontal_, _parietal_, and =supra-occipital= as before. Lying external to the middle of the _median ethmoid_ is seen the small _nasal_ (fig. 11, 8), and below the hinder part is the _lachrymal_. The _lachrymal_ (fig. 11, 9) forms the first of a series of seven small bones which surround the orbit forming the =orbital ring=. Of these the one lying immediately in the mid-ventral line of the orbit is the _suborbital_, while the one lying in the mid-dorsal line and attached to the frontal is the _supra-orbital_ (fig. 11, 11). The orbit has a cartilaginous _sclerotic_ in which are two small ossifications (fig. 11, 13) laterally placed. BONES OF THE UPPER JAW. The =palato-pterygo-quadrate bar= is in a very different condition from that of the dogfish, it is partially cartilaginous, partially converted into cartilage bone, partially overlapped by membrane bone. It is narrow in front but becomes much broader and deeper when followed back. Its anterior end forms the =palatine= which bears teeth, and in front is completely ossified, while behind the cartilage is only sheathed by bone. Just behind the palatine the outer part of the cartilage is ossified, forming two small bones, the =pterygoid= and =meso-pterygoid=, while behind them is a larger, somewhat square bone, the =meta-pterygoid= (fig. 11, 15). Below the meta-pterygoid is a tract of unossified cartilage, and then comes the =quadrate= (fig. 11, 18). The lower angle of the quadrate bears a cartilaginous =condyle= with which the mandible articulates. In front of the palatine the cartilaginous snout is overlapped by three membrane bones, the _jugal_, _maxilla_ and _premaxillae_.