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71 Appendix.

nose throughout the whole length of the trunk. They are most
numerous and closest in the ventral and medial circumference
of the nasal tube whereas they are more scattered dorsally and
laterally, where they radiate out through a thick layer of numerous
, small lobulate glands. Also medially and ventrally there are
a number of glands imbedded between the fascicles of the rectus,
but bv no means so numerous as in the dorso-lateral circum-
ference. If the fascicles are followed along the periphery of the
nasal tube the following facts can be made out: Dorsally they are,
as we have remarked, rather scattered, thrusting up between the
glands and inserting themselves into the skin; farther down,
laterally, they are seen radiating out between the glands, then
thrusting out between the fascicles of the m. naso- and maxillo-
labialis, which in this part of the trunk only forms a thin layer
(PI. 14, fig. 3), finally to be inserted into the skin. The fascicles
turn quite smoothly down to the ventral circumference of the
nasal tube. If the ventral fascicles are followed through the
whole length of the trunk, we find that, on the proximal portion
, where the trunk ventrally borders on the intermaxillary and
maxillary bones, they are short and rather scattered, separated
from each other through rather plentiful connective adipose tissue.
Distad they increase in number and length forming, on rather
more than the distal half of the trunk, a thick mass of close
thin fibres. Some of the outmost of these, having first, near the
mucous membrane, the same direction as the rest, viz. dorso-
ventrad, take a transverse direction and form a horizontal muscular
layer (PI. 14, fig. 3, b) below the rest and above a large
ventral glandular mass. Others of the ventral rectus-nasi fascicles
(PI. 14, fig. 3, a) have an oblique direction and run obliquely
through the lateral longitudinal muscular sheath of the trunk
consisting of the pars rimana, m. nasolabialis and m. maxillo-
labialis. — If the dorsal fascicles are followed mediad, they turn,
almost imperceptibly altering their direction, down into the septum
between the nasal tubes, here running transversely from
one nasal tube to the other. Proximad they are somewhat scattered
but soon increase rather considerably in number distad,
so that they form a close layer of transverse fascicles through
the septum.

As to the rectus-bundles of the upper lip we find a continuous
layer thereof going from the horizontal layer of rectus-bundles
described above into the lateral margin of the proboscis, the
tips of the fascicles extending into the pars rimana (PI. 8, fig. 2
and PI. 14, fig. 3, c).

In the lower lip there are also rectus-bundles, traversing the
lip from the mucous to the cutaneous side.

7. HORSE.

As to the facial muscles of the Horse we shall here mention
only a few facts that are of particular interest for the investigations
in hand; otherwise referring to the accounts given in Veterinary
-anatomical treatises.

i. Platysma-sphincter-group.

The sphincter superficialis does not reach the head.

The platysma (= the m. cutaneus labiorum of the Veterinary
anatomy) arises from an aponeurosis from the occiput. The lower
part of the platysma forms a narrow, more or less continuous
muscular layer that proceeds towards the angle of the mouth,
where the fascicles are interwoven in the buccinator. The upper
part, which radiates over the masseter, shows great variations in
its development; now forming a rather continuous muscular body,
and now represented only by scattered fascicles.

The pars zygomatica is completely separated from the platysma
.

The sphincter profundus. Of this, the portio auricularis (= the
m. auricularis inferior of the Veterinary anatomy) is present. As
to the portio palpebralis we are not quite sure if the m. malaris
of the Veterinarians (PI. 8, fig. 1) is this muscle. There is con-

Facial muscles of Tapir. Horse. 72

stantly found a thin, flat muscle that extends from the crista
facialis, where it arises from the fascia, obliquely upwards and
backwards to the lower eyelid; this direction of the fascicles,
indeed, is different from that which we have otherwise found in
the portio palpebralis; but on the other hand this muscle can
hardly be considered as belonging to the orbicularis-group.

2. Orbicularis-oculi-group.

PI. 16, fig. 26; PI. 8, fig. 1.

The m. orbicularis oculi consists of circular fascicles. There
is a 777. praeorbicularis, whose dorsal portion is continued posteriorly
by a large 777. supraorbicularis extending upon the frontal
surface (the m. corrugator supercilii of the Veterinary anatomy).
As to the 777. postorbicularis we have found two small portions of
slanting fascicles that closely join the orbicular fascicles in the
upper and lower eyelid.

The muscular body of the 777. nasolabialis is frequently quite
separated from the m. orbicularis; only now and then it reaches
so far back that it immediately joins the m. praeorbicularis. The
whole of the inferior part of the m. maxillo-labialis breaks through
the m. nasolabialis so that the latter is, anteriorly, split into a
superficial and a deep (resp. a ventral and a dorsal) portion.

3. M. maxillo-labialis

(PI. 8, fig. 1.)

is, as in the Tapir, divided into two independent muscles; the
upper portion (the m. levator labii sup. propr. of the Veterinary
anatomy) being quite separated from the lower portion (the m.
caninus of the Veterinary anatomy).

4. Buccinator-group.

PI. 8, fig. 1; PI. 16, fig. 12, 13, 14.

From the anterior margin of the ramus ascendens of the
lower jaw, from the adjoining mucous membrane of the cheek
and from the upper jaw, there arises a massive bundle of longitudinal
fibres with a long narrow tendon; on the upper jaw,
the fascicles arise in a long row just above the gingiva. If we
follow the superficial longitudinal fascicles onward (PI. 16, fig. 12),
they gradually pass into a superficial layer of transverse fascicles
which, indeed, in the posterior part, are interrupted by a longitudinal
tendinous stripe from which the fascicles, running upwards
and downwards, arise. Thus, only the downwards directed
fascicles form a direct continuation of the superficial longitudinal
fascicles, whereas those running upwards appear like an independent
layer. In the anterior half, on the contrary, the transverse
fascicles run continuously from the upper to the lower jaw.

Below this transverse layer the deep longitudinal fascicles
proceed, in the form of a continuous layer, to the angle of the
mouth (PI. 16, fig. 13). From the lower margin of the longitudinal
layer a portion is split off, 777. depressor labii inf., and runs
as an extended, flat, narrow, muscular body to »the chin«.

Finally, there is, at about the middle third of the deepest
part of the cheek — close to the mucous membrane — a layer
of perpendicular fascicles (PI. 16, fig. 14). This layer also originates
from the longitudinal fascicles, a deep fascicle of the latter
bending upwards, and being continued farther on by fascicles
that gradually take the perpendicular direction.

At the angle of the mouth the superficial transverse layer
bends into the lips forming a very powerful and thick pars rimana
. The pars supralabialis (the m. incisivus superior of the
Veterinarians) is well developed, reaching with its origin almost
on to /2, and having its fascicles arranged in the usual way.

The 777. nasalis is composed of three series of fascicles, arising
from the intermaxillary bone a little above the gingiva in
the range from c to i2. Every series forms a flat, rather narrow
layer; the two hindmost run obliquely upwards and backwards
and it would seem that the fascicles end in the connective tissue
inside the m. nasolabialis and maxillo-labialis; how far they —