The thickness of the =skin= of the ox is greater than that of any of the
other domesticated animals; in general it is about 3 to 4 mm., but at
the root of the tail and the point of the hock it is about 5 mm. and on
the brisket 6 to 7 mm. The variably developed prominence at the anterior
part of the pectoral region known as the brisket consists of a fold of
skin (Plica colli ventralis longitudinalis), which contains posteriorly
a mass composed of coarse fibrous trabeculæ and fat.
The =cutaneous glands= are fewer and less developed than in the horse.
Except about the natural openings, at the point of the hock, and the
flexion surface of the fetlock, the =sweat glands= do not form a coil,
but are enlarged at the deep end and are variably flexuous. The
=sebaceous glands= are best developed about the natural openings and on
the udder, but there are none on the teats. The =naso-labial glands=
form a thick layer under the bare skin of the muzzle. They are compound
tubular glands and are lined with cubical epithelium. The openings of
their excretory ducts are easily seen.
The =hairs= are extremely variable in color and size in the different
breeds and in different individuals. The hair of the frontal region is
often curly, especially in the bull. There is no mane, and the long
hairs of the tail occur only at the end, where they form the “brush”
(Cirrus caudæ).
[Illustration:
FIG. 585.—CLAWS OF OX, VOLAR ASPECT. (After Ellenberger-Baum. Anat.
für Künstler.)
]
The =claws=, four in number on each limb, cover the ends of the digits.
Those of the chief digits conform in a general way to the shape of the
third phalanges, and each may be regarded as having three surfaces. The
abaxial or outer surface is convex from side to side, and is marked by
ridges parallel with the coronary border. Its anterior part is concave
from edge to edge, and the angle which it forms with the ground is about
30°. The interdigital or inner surface is concave and grooved; it
touches the opposite claw only at its ends. The inferior or ground
surface consists of two parts, viz., a slightly concave sole, which is
pointed in front and widens behind, and a prominent bulb of soft thin
horn, which is continuous above with the skin. The claw may be regarded
as consisting of three parts—periople, wall, and sole. The periople
surrounds the coronary border in the form of a flat band, which is about
half an inch wide, except at the heels, where it widens to cover the
entire surface. The wall forms most of the abaxial or outer part of the
claw and is reflected in front upon the interdigital surface. It thins
out toward the bulb or heel, which appears, as stated above, to consist
of the thin expansion of the periople. The sole occupies the angle of
inflection of the wall; it is continuous without demarcation with the
periople of the bulb. The perioplic matrix bears relatively long
papillæ. The coronary matrix is much less developed than in the horse
and its papillæ are short. The sensitive laminæ are much narrower and
are more numerous than in the horse; secondary laminæ are not present.
The matrix of the sole is not marked off behind from that of the
periople; its papillæ are very small and close together. The matrix of
the bulbs is separated from the flexor tendon by a mass of elastic,
fatty tissue, which is analogous with the plantar cushion of the horse.
The papillæ here are long and often compound.
[Illustration:
FIG. 586.—SAGITTAL SECTION OF DISTAL PART OF FORE LIMB OF OX.
]
The accessory digits bear short conical horn capsules which resemble in
a general way those of the chief digits, and have a similar matrix,
which covers one or two nodular vestigial phalanges. From these a
fibrous band descends obliquely on the volar aspect of each chief digit
and is attached below to the distal phalanx and sesamoid bones, sending
fibers also to the elastic pad of the heel.
The =horns= (Cornua) inclose the horn processes of the frontal bones
(except in the polled breeds). They vary very greatly in size, form, and
curvature. The root or base of the horn (Radix cornus) has a thin edge
which is continuous with the epidermis. It is covered by a thin layer of
soft horn similar to the periople of the hoof of the horse. Near the
root the horn is encircled by variable rings. Toward the apex (Apex
cornus) the thickness of the horn increases till it becomes practically
a solid mass. The horn consists mainly of tubes which are very close
together, except at the rings, where there is more intertubular horn.
The =matrix= of the horn (Matrix cornus) is united to the horn process
by periosteum which is traversed by numerous blood-vessels. The matrix
at the root of the horn is thick and bears long, slender papillæ; in the
body of the horn it becomes thin and the papillæ are smaller, but
increase in size apically. Rudimentary papillated laminæ also occur.
The =skin= of the =sheep= varies in thickness from 0.5 to 3 mm., but
differs greatly in fineness and in other respects in various breeds. In
Merinos considerable folds occur on the neck. Cutaneous pouches (Sinus
cutis) are constantly present in certain situations. The =infraorbital=
or =lacrimal pouch= (Sinus cutaneus infraorbitalis) is an invagination
about half an inch in depth, which is situated in front of the inner
angle of the eye. It bears scattered fine hairs, into the follicles of
which large compound sebaceous glands open; coil glands are also
present. The secretion of the glands is fatty and forms a yellow sticky
covering on the skin when dry. The =inguinal= (or mammary) =pouch=
(Sinus cutaneus inguinalis) is much more extensive, and is situated in
the inguinal region in both sexes. The skin of the pouch bears scattered
fine hairs and contains well-developed sebaceous glands and exceedingly
large coil glands. The =interdigital pouch= (Sinus cutaneus
interdigitalis) is a peculiar tubular invagination of the integument
which opens at the anterior part of the interdigital cleft. On sagittal
section it appears as a bent tube, an inch or more (ca. 2.5 to 3 cm.) in
length, and about a fourth of an inch (ca. 6 to 7 mm.) in diameter. The
pouch extends downward and backward, and then curves sharply upward
between the distal ends of the proximal phalanges. Its deep blind end is
somewhat ampullate. The subcutis forms a capsule around it. The skin of
the pouch is thin and pale; it bears fine colorless hairs, the follicles
of which receive the secretion of several sebaceous glands. The coil
glands here are compound and very large; they open into the
hair-follicles or directly into the pouch. The secretion of the glands
is a colorless fatty substance. The skin is covered in great part by
wool, which is similar in structure to hair, but is finer, curly, and
usually contains no medullary cells. The follicles of the wool are
curved, and are arranged more or less distinctly in groups of ten or a
dozen, several of which open in common on the surface. A considerable
part of the face and the limbs is covered with short, stiff hair, and
long hairs occur more or less interspersed among the wool. The claws
resemble those of the ox. The horns, when present, are more or less
prismatic, distinctly ringed, and vary in length and curvature in
different breeds. Their structure is similar to those of the ox.
The olfactory and gustatory organs resemble in general those of the
horse.