41 



to and parallel with the premaxillary, which it resembles in form, but U longer and thinner. 

 The expanded and bifurcate end of the maxillary U produced inwards rather than upward*, 

 and form* a socket on which the ascending or nasal process of the premaxillary glide* : a 

 tubercle at this end of the maxillary i* attached to the palatine, and ligaments 

 the same expanded end to the naaal, the turbinal, the vomer, and the prcmaxil- 

 lary : the lower and hinder expanded end of the bone is attached by strong elastic liga- 

 ment, in which a labial griitle i* developed, to the coronoid process of the lower jaw. 



The premarillary (tt), one of a symmetrical pair of bones, is moderately long and slender, 

 slightly curved, expanded and notched at both extremities : the anterior end is bent upwards, 

 forming the naaal process, and is attached in the recent head by lax ligaments to the nasal 

 bone and prenasal cartilage, to the palatine, and to the anterior end* of the maxillary bone*. 

 The premaxillaries are moveably connected to each other by their anterior ends ; the naaal 

 processes are separated by the prenasal cartilage, the lower or outer branches project freely 

 downwards and outward* ; the labial or alveolar border of each premaxillary is beset with 

 teeth. 



The entopteryyoid (u) is an oblong, thin, scale-like bone, attached to the inner border of 

 the coaiUptcd halves of the palatine and true pterygoid, and increasing the bony roof of the 

 mouth in the direction towards the median line. It is edentulous in the Cod. 



The ptrrygtnd (t) form* an inequilateral but more elongated triangular plate than the 

 palatine, with which it is dovetailed anteriorly ; it becomes thicker towards its posterior 

 end, which is truncated and firmly engrained with the anterior border of the hypotympanic 

 and pretympanic bones ; its lower border is smooth, thickened and concave : edentulous in 

 the Cod. 



The pedicle supporting the lower jaw U divided into four pieces. The superior piece, or 

 rpttympamie (), is articulated to the postfrontal and mastoid by a single elongated randy le ; 

 below which it become* compressed laterally, but much expanded from before backward*. 

 Its lower portion is bifurcate. The anterior division articulates with the preopercular (tt), 

 the meaotympanic (), and pretympanic (tsr) ; the posterior division is again bifurcate, 

 supporting part of the preopercular and part of the opercular bone. A strong crest projects 

 from its outer surface. 



The metotympanie (ts), or 'lymplectic* of Cuvier, i* a (lender, compressed, slightly 

 curved, elongated, triangular bone ; articulated by its upper part or base to the epityropanic 

 and preopercular ; by its lower end to the inner side of the hypotympanic, reaching almost 

 to the mandibular trochlea, and by its anterior border to the pretympanic. 



The prttympanic (at*), to which part of the suspensory pedicle of the jaw Cnvier re- 

 strict* the name ' caisse ' or ' oa tympanicum,' i* an oblong bony scale, with the posterior 

 margin thickened and grooved for the reception of the fore-part of the meaotympanic and the 

 upper and fore-part of the hypotympanic. 



The kypolympmmie (*') i* a triangular plate of bone, like the epitympanic reversed, bear- 

 ing the articular convex trochlea for the lower jaw upon its inferior apex, and having its 

 upper side or base more even than the opposite base of the epitympanic. The posterior 

 margin of the hypotympanic i* grooved for the reception of part of the preopercular (M); 



