8 PEOF. HUXLEY ON THE SPECIFIC AND GENEEIC 



canine groove to the ends of the ossa quadrata. The nasal 

 aperture is pyriform, its wider end being forwards, and its narrow 

 posterior extremity, into which the pointed ends of the nasal bones 

 project, attaining the level of the first tooth behind the canine 

 groove. 



On the left side there is only a pit for the reception of the 

 anterior mandibular tooth, while on the right side tliis pit is con- 

 verted into a complete foramen. On the upper face of the skull, 

 the premaxiUo-maxillary suture runs vertically upwards through 

 the canine groove, and then passes obliquely backwards to a point 

 5 inches behind the end of the snout. The anterior part of this 

 suture lies in a strong ridge, which is continued downwards and 

 forwards on the premaxiUa to the level of the fifth tooth, a groove 

 separating it from the margin of the nasal aperture. Posteriorly 

 this ridge dies away, but a curved irregular elevation, convex 

 inwards, arises opposite the tenth tooth. It is wholly confined to 

 the maxilla, not extending on to the nasals. 



There is a distinct, rough, irregular elevation, bounded on its 

 outer side by a sharp groove, which extends back to the orbit, on 

 the lachrymal bone. The profile of the skull is convex as far as the 

 posterior boundary of the nostril,and very slightly concave from that 

 point as far as the twelfth tooth. It then passes back as a straight, 

 slightly ascending line, only interrupted by the lachrymal I'idge, to 

 the margin of the occiput. The inferior margin of the maxilla is 

 convex downwards as far as the canine groove, whose lower end 

 is indicated by a deep sinuation. It then becomes convex again, 

 the crown of the curve being at the ninth and tenth teeth, and its 

 posterior end sweeping into a concavity whose summit is at the 

 twelfth tooth. Behind this the edge of the maxilla is only slightly 

 convex. The inferior contour of the jugal bone is very concave ; 

 but the articular end of the quadrate bone descends to the level 

 of the edge of the ninth alveolus. 



The orbits liave a sort of heart-shape, their apices being turned 

 forwards, and their more convex sides inwards. 



The supra-temporal fossae are half-moon-shaped, their straight 

 sides being externa] and so inclined tliat, if prolonged, they would 

 decussate upon a line joining the anterior margins of the orbits. 



On the palatine surface of the skull, the premaxiUo-maxillary 

 suture runs backwards from the canine groove, as far as the level 

 of the middle of the second alveolus behind the groove (or that of 

 the seventh tooth), which point it reaches at about the junction 

 of the middle with the inner third of the palatine plate of the 



