310 THE HORSE. 
Suspended from the head is the os hyoides, which completes the number 
of bones. Thus :— 
THE SPINE consists of 7 cervical, 18 dorsal, and 6 lumbar vertebre— 
Total, 30 = ol 
Tus THORAX is made up of the dorsal vertebra, with 18 ribs on each 
side, and the sternum in the middle—Total. . . . o7 
THE PELVIS comprises 2 ossa innominata (or ilium, ischium, and 
pubes)vand WT sactum— otal. ..." eee eee cee eens 
THE TAIL contains on the average 17 bones. . 1 
THE FORE EXTREMITY is made up on each side of the scapula, 
humerus, os brachii, and 8 carpal Dons 3 metacarpal, os suffra- 
ginis, 0s corone, os ‘pedis, os naviculare, 2 ossa sesamoidea—Total 
on both sides. . . 40 
Tue uiNp extremity has the femur, patella, ‘tibia, ‘fibula, 6 tarsal 
bones, 3 metatarsals, os suffraginis, os coronz, os pedis, Os naviculare, 
2 ossa coeennent len Papell Sp hs Ben edn ta ee pee lem Mee eee an a 
BoNES OF THE CRANIUM. . . a) le) ai he UEP y eu, ee Cone aA 
BONES OF THE FACE AND LOWER JAW .......%s .. ss JS 
iene, ss ee erika. 4) 
Bones OF THE INTERNAL EAR, ae in weal organ’... ae 8 
Os HYOIDES, OR BONE OF THE TONGUE, made up of five sections . be, 
Grand total... = 2 Sa eeeeea 
GENERAL ANATOMY OF THE SPINAL COLUMN. 
THE VERTEBRAL OR SPINAL COLUMN is the first rudiment of internal 
skeleton seen in the lower vertebrate animals, and this constitutes the type 
of that great division of the animal kingdom. In the horse, also, it is the 
portion of the skeleton first developed in the embryo, and forms the centre 
around which all the other parts are framed. At its first appearance it is 
a cartilaginous cylinder, surrounding and protecting the primitive trace of 
the nervous system; but as the embryo increases in growth, points of 
ossification are developed corresponding to each vertebra, the whole tube 
being finally divided into distinct pieces called zertebre, to which the 
bones of the head are a prolongation, corresponding in their nature, 
though differing outwardly in form. 
The vertebroe are divisible into true and false, the former reaching from 
the head to the pelvis, and the latter extending thence backward, being 
respectively called the sacrum and coccyx. 
The true vertebre comprise the 7 cervical, 18 dorsal, and 6 lumbar 
vertebre. Each consists of a body, from which two lamin or plates 
project upwards, terminating in a spinous process. In addition to these 
are two lateral projections (transverse processes), which serve the purpose 
of firmly connecting the vertebre together by means of the muscles 
attached to them, and also to the ribs and extremities below. Lastly, 
each vertebra has two small surfaces before and the same number behind 
(articular surfaces), which form distinct joints between them. The detuils 
of these parts, and the peculiarities met with in each set, will be described 
in the next chapter. 
Between the body, the lamin, and the spinous process, is an opening, 
more or less triangular in shape, in which lie the spinal cord and its 
investments. The “edges of this epeuing are attached to those before and 
