392 Miscellaneous. 



bifurcated end ; one division being facial, tbe other palatal. The 

 latter begins by a point at the fore-part of the palato-nasal aperture ; 

 it gradually expands as it advances, underlapping the maxillary and 

 palatine bones, and entering into the formation of the alveolar 

 groove at about the fifteenth tooth. The facial plate of the pre- 

 niaxillary begins behind by a bifurcated end, the notch bounding the 

 fore-part of the external nostril ; the vertical plate slowly expands, 

 overlapping the nasal and maxillary and gradually descending to the 

 alveolar border, so as to conceal the maxillary at a distance from 

 the nostril equal to the length of that aperture. The premaxillaries 

 form the major part of the upper jaw. The facial plate is impressed 

 by a longitudinal groove near its lower border. 



The pterygoid begins behind by a triradiate expansion ; the outer 

 short and broad ray or process, abuts against the inner side of the 

 lower end of the tympanic ; the upper narrower ray ascends to be 

 wedged between the paroccipital, mastoid, and tympanic ; the inner 

 longest ray is broad and flat, obtusely pointed, and wedged between 

 the paroccipital and basisphenoid. In advance of this triradiate 

 expansion the pterygoid contracts, presenting a concave inner border, 

 which articulates with the side of the basisphenoid, and a mxore 

 concave outer border, which forms the inner boundary of the cavity 

 which was occupied by the cartihgiuous petrosal. The bone again 

 expands, its outer border forming an angular process, to the fore- 

 part of which the ectopterygoid unites ; the body of the pterygoid 

 then extends as a rather narrow plate of bone obliquely inwards, 

 bounding the pterygo-sphenoid vacuities, and articulating externally 

 to the ectopterygoids, towards the fore-part of which the pterygoid 

 more rapidly contracts, and is continued some way further forwards 

 as a pointed styliform process, internal to the palatine, and coming 

 into contact with the opposite pterygoid near their pointed ends, 

 which form the mid-part of the bony palate. 



The ectopterygoids are long plates of bone, with a rounded obtuse 

 hinder end ; very gradually expanding to where they join the pala- 

 tine, then rapidly contracting to a styloid process, forming the 

 hinder and outer boundary of the palato-nasal opening, and uniting 

 there with the maxillary. 



The malar is peculiarly long and slender, commencing anteriorly 

 by a pointed end wedged between the maxillary and lacrymal, as- 

 suming the form of a round, slender, slightly bent bar, which ex- 

 pands a little to be wedged, at the back of the orbit, between the 

 post-orbital and squamosal. A long vacant space, the lower outlet 

 of the temporal fossa, divides the body of the malar from the ecto- 

 pterygoid and pterygoid. 



The squamosal* is a short and small subquadrate bone, with 

 three of the angles produced, the fourth thickened into an articular 

 or sutural surface. The upper and anterior angle is wedged be- 

 tween the super-squamosal and post-orbital, the lower and anterior 

 angle underlaps the end of the malar ; the upper border unites with 



* Os zygomaticum in ' Report of Brit. Foss. Reptiles,' 1839, p. 92. 



