OSTEOLOGY OF THE HORSE. 69 



Development of the Teeth. — The teeth with which the young- 

 animal is provided, are, at certain intervals of age, cast off and 

 replaced by others : hence the distinction of these two sets into 

 temporary and permanent teeth. The temporary/ teeth are twenty- 

 four in number — twelve incisors, and twelve molars. The tempo- 

 rary incisors differ from the permanent — 1st, in being smaller and 

 whiter; 2dly, in having necks or contractions where the root joins 

 the body ; 3dly, in their fangs being slenderer and more pointed. 

 The temporary molars differ from the permanent set — 1st, in 

 number; 2dly, in being, individually, smaller and whiter; 3dly, 

 in the eminences upon the faces being sharper. 



OF THE ARTICULATIONS OR JOINTS OF 

 THE SKELETON. 



TRUNK. 



Akticulations between the occiput, atlas, and axis. 

 —The condyles of the os occipitis are embraced by the smootii 

 excavations forming the inner sides of the atlas: these articulary 

 surfaces are covered with cartilage, and the two bones are fasten- 

 ed together, by — 1st, Lateral ligaments, passing from the coro- 

 noid processes of the occiput to the fore parts of the body of the 

 atlas, to be fixed to the roots of its transverse processes ; 2d, The 

 suspensory ligament of the head, fixed to the body of the atlas, 

 between its anterior articular processes and the upper border of 

 the occij)ital hole; 3d, The capsular ov synovial membrane, at- 

 tached to the body of the occiput, around the roots of the condy- 

 loid processes, and to the body and anterior articular processes of 

 the atlas. It detaches a process to the membranous envelope of 

 the odontoid projection, by which all communication is cut off 

 between the joints formed by the first and second vertebrae. 



The axis articulates with the atlas, but is also connected with 

 the occiput. It has — 1st, The superior ligament, passing from 

 the spine of the axis to the inferior part of the bony ring of the 

 atlas; 2d, The inferior ligament, broad, connecting their inferior 

 spinous projections together ; 3d, The three odontoid ligaments : — 

 two long, passing from the sides of the odontoid process to the 

 inner sides of the occipital condyles ; the short and broad one, 

 running from the point of the process, along a bony canal, to the 

 antero-inferior part of the atlas ; 4th, Capsular membrane, in- 

 cluding the articulatory surfaces, which are encrusted with carti- 

 lage, of the first and second vertebrte, is attached around the pos- 

 terior articular processes of the atlas and tlie anterior of the axis, 

 around the odontoid process, and also to the odontoid ligaments. 



