194 SKELETON OF THE DOG 
of the lateral boundaries of the posterior nares. The lower and posterior borders 
are free and at their angle of Junction there is a variable hamulus. 
The nasal bones are (in most breeds) long and wider in front than behind. 
The facial surface is variably concave in its length and is inclined toward the 
median suture so as to form a central groove. The medial borders turn downward 
and form an internal nasal crest which becomes very prominent behind. The pos- 
terior parts fit into a notch formed by the frontal bones. The anterior ends form 
an almost semicircular nasal notch. 
The lacrimal bone is very small. The facial part extends very little or not 
at all beyond the orbital margin. The orbital surface is small and triangular, 
and presents the entrance to the lacrimal canal. 
The large zygomatic process constitutes the bulk of the malar bone. It is 
very long and is strongly curved. The dorsal border is convex, free in front, where 
it forms part of the orbital margin, beveled behind for articulation with the similar 
process of the temporal bone. Between these it bears an eminence, the processus 
frontalis, to which the orbital ligament is attached. The body of the bone may be 
considered to consist of a lacrimal process directed dorsally and fitting in between 
-— 
{eR 
/, 5 
[ Coronoid 
v/, process 
Incisor Canine Premolar / Mandibu- 
teeth tooth ; Molar / lar notch 
teeth teeth ; ew Gondil 
$e “> Conayle 
~~ Angular 
Symphyseal process 
surface 
Mandibular 
foramen 
Fig. 213.—Ricuar Hair oF MANDIBLE OF Doc; MepiaL VIEW. 
the lacrimal and maxilla, and a maxillary process directed ventrally. The facial 
surface 1s convex. 
The dorsal turbinate bone is in its anterior part a simple plate, attached by 
one edge to the nasal bone; it curves ventro-medially, and its free border is thick- 
ened and everted. The posterior part is wider and resembles the ethmoturbinates, 
with which it is connected. 
The ventral turbinate bone is short and very complex. It is attached to the 
nasal surface of the maxilla by a basal lamina, which divides into two secondary 
lamellee. The latter detach numerous tertiary lamelle, which are coiled and have 
thick free edges. 
The vomer is not in contact with the posterior part of the floor of the nasal 
cavity, and does not divide the posterior nares. The posterior end is narrow and 
deeply notched. Near the posterior nares the two plates curve outward and join 
the palatine bones and assist in forming the lamina transversalis. 
The two halves of the mandible do not fuse completely even in old age, so that 
there is a permanent symphysis mandibule. The body presents six alveoli for the 
incisor teeth and two for the canines. The incisor alveoli increase in size from first 
to third. The canine alveoli extend deeply downward and backward. The rami 
diverge less than in the pig. The ventral border of the horizontal part is convex 
in its length and is thick and rounded. The alveolar border is slightly concave in 
