SKULL AND OTHEK BONES OF LOXOMMA ALLMANNI. 199 



of the posterior third with the anterior two-thirds of the inter- 

 parietal suture. It is circular, perforates the top of the cranium, 

 and opens below as a smooth, inverted funnel-shaped cavity. 



The broad channels or fossae leading to the external auditory 

 openings, the temporal fossa, are bounded on the inner side by 

 the squamous and mastoid bones, and, notwithstanding that the 

 skull has been subjected to immense pressure, are still seen to 

 be at a somewhat lower level than those bones. They pass for- 

 ward for about an inch from the external posterior angle of the 

 mastoid, are rounded off outwardly in front, their floor becoming 

 gradually more superficial on the supra-temporal bones; these 

 constitute nearly the whole of their floor, the narrow parts of 

 which left on the inner sides are supplied by the ossa quadrata. 



External to these fossse, extend broadly outward and back- 

 ward, for nearly two inches behind the posterior border of the 

 occiput, the posterior expansions of the sides of the cranium, or 

 extensions of the maxillge. 



Individual bones. — These can be distinguished, with a little 

 trouble, by observing the lines of suture along which they are 

 united. 



The premaxillaries form the whole of the front of the snout, 

 and are firmly united on the median line ; they are bounded be- 

 behind, on each side of the mouth, by a small portion of the 

 maxillaries, which in part they overlap ; further in, by the nasal 

 orifices, and next by the nasal bones. 



The maxillaries occupy the edge of the upper jaw, from the 

 outer ends of the premaxillaries and the nasal orifices to the 

 suture uniting the malar and quadrate jugals, a distance of nine 

 inches and a half; they are seen from above as far as a point 

 nearly opposite to the middle of the length of the orbital vacui- 

 ties. These bones nowhere measure more than three-quarters 

 of an inch in breadth ; behind the broadest part they rapidly be- 

 come narrower, and form a mere bordering to the jaw, and are 

 only here and there visible from above. Their inner borders 

 unite in front for an inch with the nasals, then for two inches 

 and three-quarters with the lacrymals, and further back with 

 the malars. 



