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65 Appendix.

Posteriorly the m. orbicularis is joined by a rather broad
tract of postorbicular fascicles.

The m. prceorbicularis is powerful. The ventral fascicles form
a direct continuation of the sphincter-fascicles in the lower eyelid;
but in front, the • line of origin gradually proceeds higher and
higher, so that the anterior downward radiating fascicles, arise
rather high above the anterior angle of the eye. — The dorsal
fascicles begin at the anterior angle of the eye extending backwards
nearly the whole length of the upper eyelid. Thus the
m. prseorbicularis dorsalis proceeds direct into the m. supraorbi-
cularis which therefore does not form a separate »muscle«. The
fascicles form together a broad but thin muscular plate that extends
high upon the front, especially is this the case with its
anterior fascicles.

The m. nasolabialis by a long interval is separated from the
rest of the orbicular complex (PI. 9). It arises from about the
anterior half of the dorsum of nose, where its origin almost
reaches on to the anterior end of the nasal bone. The fascicles run
downwards, the posterior ones also obliquely forwards, whereas
the anterior gradually take more and more a transverse direction.
Only the posterior fascicles reach quite down into the upper lip,
where in the fold above the canine they thrust in between the
rimana-fascicles. In front the fascicles gradually grow shorter,
reaching only a short distance down the side of the upper lip,
where they end in the skin being interwoven with the bundles
of the m. nasalis.

3. M. maxillo-labialis

(PI. 9)

forms a rather powerful muscular mass which arises from the
lachrymal, zygomatic and maxillary bones, in the region above
and behind the foramen infraorbitale. It divides into three portions
: an upper, a middle and a lower, of which the latter apparently
may be separated from the others from its origin. In
depth, however, it is connected with the middle portion. This
undermost portion forms a rather short but powerful round
muscular body, which, with a long strong tendon, proceeds into
the snout in the lower part of which it inserts itself, being split
into several thin branches. The second, or middle, more fleshy
portion, arises closely connected with the uppermost, gradually
separating from it and radiating into the snout with a row of thin
tendinous branches. The uppermost portion is the most powerful
, and thickest, at the origin, where it is separated from the
undermost portion by a narrow fissure filled with adipose tissue.
After having separated from the middle portion, a little farther
on it passes into a strong flat tendon that proceeds forwards,
turning at last, at the anterior end of the nasal bones, on to the
dorsum of nose where it joins the corresponding one inserting
itself into the upper part of the snout. In this muscle there is
a point that somewhat recalls what obtains in the Wapiti (comp.
PL 11, fig. 5 a, b): To wit, from the tendon, immediately where
it passes out of the muscular body, there arises a rather powerful
fascicle that posteriorly passes immediately into the muscular
body, taking otherwise its origin, for a couple of centimeters,
from the lower margin and the inner surface of the tendon. The
fascicle runs obliquely forwards, and downwards, lying mostly
immediately over the bones, and inserting itself into the intermaxillary
bone just above the origin of the m. nasalis. It is
hardly to be doubted that it is really a fascicle of the portio
superior m. maxillo-labialis. One might perhaps imagine that it
were a fascicle of the m. nasalis which had inserted itself into
the tendon of the portio superior (cornp. e. g. the relations between
the nasolabialis and the maxillo-labialis in some Mammals).
But it seems to us that partly from the direction of the fascicles
and partly and more particularly from the close connection with
the muscular body of the portio superior of the m. maxillo-
labialis the former conception appears by far the more probable.
Also, with respect to the uppermost tendon of the middle portion
, there is something similar, but here, indeed, it is only
quite a thin narrow fascicle which from the muscular body ex-

Facial muscles of the Boar. Tapir. 66

tends obliquely downward and forward inserting itself into the
intermaxillary bone.

4. Buccinator-group.

PI. 16, fig. 15, and PL 9.

At its origin posteriorly from the upper and lower jaw the
m. buccinatorius only forms one layer of longitudinal fascicles,
but about midway the cheek, at a distance in front of the
masseter, there is a crossing, part of the lower fascicles crossing
obliquely up over the upper ones, and being continued farther
forwards by transverse fascicles; so the buccinator appears with
two layers in its anterior part: a superficial layer of transverse
fascicles, and a deep layer of longitudinal fascicles.

The transverse layer forms rather a powerful stratum of fascicles
that span in the usual way from the upper to the lower jaw.
At the angle of the mouth it passes direct into the pars rimana
which, both in the upper and lower lip, forms a very full muscular
layer. In the upper lip the fascicles reach into the snout.
The pars supralabialis is greatly reduced; it is present only in
the fold which the upper lip forms over the canine. On this
space there arises a group of fascicles from the maxillary bone
close above the gingiva extending in an arc downward, and forward
, into the upper lip.

The rather powerful longitudinal layer proceeds inside the
transverse layer ending at the angle of the mouth; some of the
lower fascicles, however, reach into the under lip where they
mingle with the fascicles of the pars rimana.

Finally there is a well marked m. depressor labii inferioris.
It begins quite posteriorly, where it is to some extent intimately
connected with the longitudinal fascicles of the buccinator, thereafter
separating as a well defined, extended, muscular body, that
soon passes into a bundle of thin tendinous branches that insert
themselves into the under lip. The m. depressor is further limited
from the rest of the buccinator by the fascicles of the platysma
thrusting between these two (v. PL 9, where only the tendinous
branches of the m. depressor are visible in front of the platysma;
whereas the rest of the muscle is covered by the latter).

The m. nasalis (PL 9) forms a considerable muscular mass,
the bundles of which arise in rows partly from the intermaxillary
bone, partly outside the cartilaginous nose. The fascicles radiate
outwards to the skin, the lower ones down into the upper lip,
partly crossing out between the tendinous branches of the m.
maxillo-labialis.

The m. mentalis (PL 9) also forms a very considerable muscular
mass that arises from the lower jaw, the mostly coarse
fascicles radiating down into the under lip and the »chin«.

The /77. lateralis nasi is wanting.

6. TAPIR.

(Tapirus americanus.J
1. Platysma-sphincter-group.

PL 7.

The sphincter superficialis is wanting on the head.

The platysma is extremely well developed, forming a continuous
, and by no means thin muscular plate over the lower
part of the face. The muscular body begins on the anterior
part of the ventral face of the neck; the inferior fascicles extend
farthest back, whereas the origin of the superior ones reach
farther and farther forwards the higher they lie, so that the
whole muscular body, posteriorly, ends in a line running
obliquely upwards; above this line the muscular body is continued
by a fascia upward on the neck (in PL 7 this fascia has
been dissected off). In the specimen investigated there was much
adipose tissue imbedded in this fascia, as also in that part of
the muscle situated nearest the origin; narrow stripes of loose
adipose connective tissue extend between the fascicles, forcing
them as it were somewhat from each other.

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