478 



ANATOMY OF VERTEBEATES, 



328 



Two of the most remarkable of these bony walls are placed at the 

 front and back part of the base of the horns, interceptmg a large 

 sinus immediately over the middle of the cranial cavity, and 

 from a third and larger one behind. The pre-sphenoidal sinuses 

 are of a large size.^ 



The chief peculiarity in the skull of the Deer-tribe is the 

 annual development, from the frontals, of the solid deciduous 

 exostoses which serve as weapons (fig. 326, d, h) during a portion 

 of the year, in the males of all kinds and in both sexes of the 



Rein-deer. Most species likewise 

 show vacuities between the frontal, 

 8, nasal, 7, maxillary, 2, and lacry- 

 mal, as in figs. 327 and 328. The 

 base of the zygoma is perforated 

 by a vein from the lateral sinus. 



The chief peculiarity of the skull 

 of the Elk (^Alces) is seen in the 

 great length of the premaxillaries 

 and of the edentulous portion of 

 the maxillaries, and in the short- 

 ness and breadth of the nasal bones, 

 which do not join the premaxilla- 

 ries. The vomer is carinate be- 

 neath. 



In the Eein-deer ( Tarandus) the 

 antlers spring from within an inch 

 of the superoccipital crest, and the 

 frontal bones are proportion ably 

 extended backward on each side of 

 the parietal, in which the sagittal 

 suture becomes obliterated : the 

 frontal suture is persistent, and is complex in its dentations at its 

 posterior half. The large lacrymal presents two canals upon its 

 orbital border and a deep oblong depression on its facial surface, 

 above which is the vacuity leading to the olfactory chamber. 

 The premaxillaries do not join the nasals. In the Fallow-deer 

 (Dama) the frontal bones do not extend so far back as in the 

 Rein-deer, and the antlers, in consequence, rise at a greater 

 distance from the occipital crest. The lacrymal bone has two per- 

 forations at its outer border, and its facial plate is nearly equally 

 divided into an upper convex and a lower concave surface. The 

 antorbital depressions show but a small perforation, if any. 



' XOVII-, p. 235. 



Skull, Cerviis Mantjak. 



