66 THE SKELETON OF THE HORSE 
and nasal, are smooth and rounded. The dorsal border is free, thick, and smooth; 
it concurs with the free margin of the nasal bone in forming the naso-maxillary 
notch (Incisura nasomaxillaris). The ventral border is dentated and joins the 
maxilla; at its anterior end it forms with the latter the alveolus for the permanent 
canine tooth.! The posterior ex- 
tremity fits into the interval be- 
tween the nasal bone and the 
maxilla. 
The palatine process (Pro- 
cessus palatinus) is a thin plate 
which forms the anterior part of 
the basis of the hard palate. Its 
nasal surface (Facies nasalis) has 
a longitudinal ridge which forms 
with that of the other side a groove 
for the septal cartilage; lateral to 
the ridge there is a groove for the 
vomero-nasal organ. The palatine 
surface (Facies palatina) is flat. 
The medial border is serrated and 
meets its fellow at the median pala- 
tine suture. The lateral border is 
separated from the maxilla and the 
nasal process by the palatine fis- 
sure (Iissura palatina). The pos- 
terior extremity fits into the inter- 
val between the vomer and the 
palatine process of the maxilla. 
Development.—The premax- 
illa ossifies from a single center. 
Fusion of the two bones is com- 
plete at the end of the third or 
the beginning of the fourth year. 
THE PALATINE BONES 
The palatine bones (Ossa pala- 
tina) are situated on either side of 
the choanz or posterior nares, and 
Fic. 43.—Urrer Jaw or Horse Anovut Four anp a HALF form the posterior margin of the 
SAS OLD RONG ay oe hard palate. Each is twisted so as 
1, 1, Choane or posterior nares; 2, vomer; 3, horizontal . 
to form a horizontal and a perpen- 
part of palatine bone; 4, anterior palatine foramen; 5, palatine 
groove; 6, transverse palatine suture; 7, median palatine suture; dicular part. 
8, palatine process of maxilla; 9, palatine process of premaxilla; The horizontal part (Pars hori- 
10, foramen incisivum; 11, malar bone; 12, maxilla; 13, anterior sen oon ? . 1 5 h 
end of facial crest; 14, interalveolar space; I. 1-3, incisor teeth; zontalis) IS a Narrow p ate whic 
C, canine tooth; P.1, first premolar or “wolf” tooth. The forms the posterior part of the 
opening lateral to 9 is the palatine fissure. hard palate. It presents smooth 
nasal and palatine surfaces (Facies 
nasalis, palatina). The medial border mects its fellow at the median palatine 
suture, on the nasal aspect of which is the nasal crest. The anterior border joins 
the palatine process of the maxilla at the transverse palatine suture, and forms with 
it the anterior palatine foramen (Foramen palatinum anterius). The posterior 
border is concave and free; it gives attachment to the aponeurosis of the soft palate. 
| The alveolus for the temporary canine is commonly formed in the maxilla alone. 
