On the ventral surface of the cranium in front of the basi-occipital is seen the _parasphenoid_, a very long narrow bone which underlies the greater part of the cranium. Behind, it articulates dorsally with the basi-occipital and dorsolaterally with the pro-otics and opisthotics, in front it articulates dorsally with the lateral ethmoid and ventrally with the vomer. At the sides of the parasphenoid are the small =alisphenoids= articulating above with the postfrontals, in front with the frontals, and behind with the pro-otics. The _vomer_ is an unpaired bone lying immediately in front of the parasphenoid. In front it terminates with a thickened curved margin bearing several rows of small teeth; behind it tapers out into a long process which underlies the anterior part of the parasphenoid. Immediately dorsal to the vomer is another median bone, the _median ethmoid_; this is truncated in front and tapers out behind into a process which fits into a groove on the ventral side of the frontal. BONES IN CONNECTION WITH THE UPPER JAW. These bear a close resemblance to those of the Salmon. The most anterior bone is the _premaxillae_, a thick curved bone meeting its fellow in the middle line. The point of junction of the two is drawn out into a short process, and the oral surface is thickly covered with small teeth. The dorsal ends of the premaxillae are seen in the fresh skull to meet a large patch of cartilage. Behind the premaxillae is the _maxilla_, a long rod-like toothless bone, somewhat expanded at the upper end where it articulates with the premaxillae and vomer. Articulating in front with the anterior end of the maxilla and with the =lateral ethmoid= is a very irregular bone, the =palatine= (fig. 12, 1); it articulates behind with two flat bones, the =pterygoid= and =meso-pterygoid=. The pterygoid is united behind with two more bones, the =quadrate= (fig. 12, 4) and =meta-pterygoid=. The =quadrate= is a rather stout irregular bone, bearing on its lower surface a prominent saddle-shaped articulating surface for the mandible. The palatine, pterygoid and quadrate bones are the ossified representatives of the palato-pterygo-quadrate bar of the Dogfish. [Illustration FIG. 12. MANDIBULAR AND HYOID ARCHES OF A COD (_Gadus morrhua_) × 1/2 (Brit. Mus.). 1. palatine. 2. meso-pterygoid. 3. pterygoid. 4. quadrate. 5. symplectic. 6. meta-pterygoid. 7. hyomandibular. 8. angular. 9. articular. 10. dentary. 11. inter-hyal. 12. epi-hyal. 13. cerato-hyal. 14. hypo-hyal. 15. uro-hyal. 16. branchiostegal rays.] The quadrate is united behind with the =symplectic= (fig. 12, 5), and the meta-pterygoid with the symplectic and =hyomandibular=, both of which bones will be described immediately in connection with the hyoid arch. THE LOWER JAW.