3S4 
Lamenesses of Sheep and Lamhs. 
bone behind it — the navicular or shuttle bone. The coffin-bone 
Ijino; deeply buried in the hoof is triangular, giving to the hornv 
covering its characteristic shape. The abutment of the small 
pastern comparatively far back upon the coffin-bone imparts to 
the pasterns of the sheep their peculiar upright appearance. 
We pass over the several muscles in the upper part of the 
limits employed in flexion and extension. To describe them 
witliout diagrams would be difficult and uninteresting. The 
flexor tendon of the foot situated on the posterior part of the 
limb arises in tlie fore leg from the back part of the humerus, in 
the hind from the back part of the femur. A little above the 
knee it becomes double. The outer part is flattened and forms a 
sheath for the inner. At the end of the shank-bone both tendons 
bifurcate, a division going to each of the digits ; they are inserted 
into the second and third phalanges. The extensors of the foot 
arise from and are inserted into the same bones as tlie flexors, 
but occupy the front instead of the back of tlie limb. Two check 
ligaments pass from the bones, are fixed into the flexor tendons 
of each limb, and prevent over-extension. When the tendon is 
stretched to a certain extent the check ligaments attached to it 
come into play, and from their other end being fixed into the 
unyielding bone counteract undue extension. The suspensory 
ligament arising from the head of the shank-bone and passing in 
front of the flexor tendons to the pasterns below also aids these 
check ligaments in preventing over-extension. Besides these, a 
strong ligamentous band connects the upper ends of the coffin- 
bones, retaining the digits in apposition. This beautiful me- 
chanism of tough chords is constantly lubricated by actively 
secreting pouches, or bursse, through which they pass, and which 
are especially well developed where the tendons are exposed to 
friction in passing over a bony prominence or playing over a fi'e- 
quently-moved joint. So exquisitely are the several parts of this 
locomotive apparatus adjusted to each other, and so effective the 
many adaptations for gaining strength, that accidents and injuries 
are exceedingly uncommon. The fact too of sheep being seldom 
exposed to severe over-exertion also renders them less liable than 
many other animals to ligamentous or tendinous lesions. 
Tlie skin investing the leg is thick, and ought to be well covered 
with hair, which becomes short and brush-like behind. It moves 
freely over the subjacent textures, being loosely attached to them 
by a thick layer of cellular tissue. It consists of two strata : an 
insensible non-vascular epidermis or scarf-skin made up of flat- 
tened cells and scales, and covering the deep stratum, dermis, or 
true skin, which consists of fibrous tissue with numerous blood- 
vessels and nerves. This layer produces the hair, which is but an 
altered form of the epidei'mal covering. Imbedded in its structure 
