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Elephant.

Platysma. Orbicularis-oculi-group.

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whole muscle thereby becomes fanshaped: narrow, but thick and
rather strong at the insertion — flat, broad and separated in several
portions at the origin. The whole line of origin, which
forms a bow, convex posteriorly, nearly reaches the middle of
the masseter; and the upper portion is some distance from the
zygoma. Dorsad the muscle is continued into a thin aponeurosis,
which vanishes over the zygoma. — On the right side of the
head (PI. 1) the angular portion consists of two well marked
branches (d and e), to which furthermore joins the uppermost
branch (c) of the mandibular portion; all three branches converge
a little behind the angle of the mouth, where they project into
the m. buccinatorius, the branches d and e here join closely.
The branch d arises on the middle of the masseter from the aponeurosis
. The uppermost branch (PI. 1, e), however, turns its hindmost
end backwards and upwards and in the aponeurosis there
is a thickened portion (PI. 1, /) which is inserted on the lower
edge of the zygoma, and which may easily be dissected out as
a separate tendon of the uppermost branch; or, in other words,
on this side of the head there is formed a strongly marked pars
zygomatica platysmatis, which, however, shows its close connection
with — or we might say — its origin from the platysma
by the very intimate cohesion with the rest of the angular portion
. In comparison with this the left side shows a more primitive
state, as a distinct (separate) portion of the platysma, which
may be designated as a »pars zygomatica«, has not yet been
singled out here.

As mentioned above, the fascicles of the angular portion join
and project into the buccinator a little behind the angle of
the mouth. The buccinator and the platysma are here quite
interlaced; the bundles of the platysma, in several rows (v. PI. 4),
one behind the other, projecting between the bundles of the
buccinator; farther on they join the longitudinal bundles of this
muscle.

Upon the whole the relation of the pars zygomatica to the
rest of the platysma in the Elephant examined appears with the
stamp of a more primitive state than that found in the Ungulates
(vide General Part p. 9). Only in Alces is there still found some
connection between them, but not by any means to such an extent
as in the Elephant.

In some respects the platysma of the Elephant resembles
that of the Ungulates. We find in both of them the great reduction
of the cervical portion which is wholly transformed into an
aponeurosis. But in the Elephant the muscular part of the platysma
is also somewhat reduced, since it corresponds only to
the lower part of the pars principalis (+ pars zygomatica) in the
Ungulates; thus it most resembles that of the Camel (PI. 5). In
all the other Ungulates examined there is besides an upper part
of the pars principalis which, now as a continuous muscular plate
(Wapiti, Boar, Tapir), now as more or less separated bundles
(Bos, Horse, Elk), crosses the masseter; all this upper part of
the pars principalis is wanting in the Elephant. The part of the
platysma which remains shows several peculiarities, has undergone
considerable modifications which no doubt are rather closely
connected with the transformation that the whole face of this animal
has undergone. The continuous lower part of the pars principalis
of the Ungulates has, in the Elephant, been split into two
well marked portions, an angular portion and a mandibular portion
, and the origin of the angular portion has been raised considerably
on the outside of the masseter. Last but not least, the
direction of the fibres must be observed. In the Ungulates they
are longitudinal, in the Elephant, however, they ascend in an
arc and converge towards the angle of the mouth. These alterations
of the platysma, no doubt, stand in close connection with
the abbreviation of the face, by which the angle of the mouth
has been drawn so far back (almost under the eye), partly they
are evidently due to the fact that the angle of the mouth has
been raised so much in the Elephant.

The accounts of the platysma in Watson1) (»panniculus car-

x) Contributions to the Anatomy of the Indian Elephant. Part IV. Muscles and
Blood-vessels of the face and head, in: Journ. of Anat. and Physiol. Vol. 9. 1874.

nosus«) and Miall and Greenwood1) (»platysma ir^oides, facial
portion of panniculus«) are very short and incomplete. They mention
the insertion of the bundles of the platysma partly into the
lower jaw partly at the angle of the mouth; but also state that
the upper bundles insert themselves into »the facial aponeurosis
below the zygoma«2). We have not found this. — The pars zygomatica
platysmatis, which in both papers is described by the
name of »zygomatico-labialis«, was evidentty present in a fully
developed form in the specimen examined by Miall and Greenwood
. But in the paper of Watson the description is rather vague.
One has the impression that his specimen presented the same
conditions as the left side of our specimen, viz. that in reality
there was no distinctly separated pars zygomatica.

2. ORBICULARIS-OCULI-GROUP.

PI. 1 ; PI. 4; PI. 16, fig. 20.

The m. orbicularis oculi (PI. 1 and PI. 16, fig. 20) is a strong,
rather thick muscle of about the same width in the upper eyelid
as in the lower; but in neither of them so wide that it goes
beyond the bony aperture of the orbit. It is a very coarse-fibred
muscle, the fascicles of which ma}^ without difficulty, be dissected
throughout their whole length. The muscle does not form a complete
ring. At the anterior angle there is a broad, thick ligamen-
tum palpebrale (anterius, nasale), from the upper and lower margin
of which the fibres arise. From the upper margin the fibres ascend
in an arc into the upper lid; the fibres that are most superficial
at the origin only reach a short distance into the eyelid and insert
themselves into the skin with pointed, short tendons. The
other fibres gradually grow longer and the longest penetrate the
whole of the upper eyelid unto behind the posterior angle, from
which some of them descend a little into the lower eyelid. In the
lower eyelid the fibres behave in a corresponding manner. At
the posterior angle the fibres meet and their free ends are intimately
interlaced. This interlacement is further complicated by
the m. postorbicularis, which begins with rather short bundles
that go round the posterior angle, and are bent in a manner
quite similar to the bundles of the m. orbicularis with which
they are interlaced. Caudad the fascicles of the m. postorbicularis
grow gradually streight, so that they at last go almost dorso-
ventrad. The whole m. postorbicularis forms a rather broad muscular
plate behind the m. orbicularis consisting of thick, coarse
fascicles which »anastomose«: a small branch parting from one
fascicle and then passing obliquely downwards to join a neighbouring
fascicle. In PI. 16, fig. 20 only a single »anastomosing«
fascicle is seen whereas the other rather numerous »anastomoses«
only become visible by spreading the bundles; especially between
the posterior fascicles of the m. postorbicularis these »anastomo-
ses« were so numerous that one might fairly speak of a reticular
arrangement of the fascicles.

In front of the m. orbicularis, covered in its middle by the
lig. palpebrale nasale, the m. prceorbicularis (PL 4) is seen, having
the form of two fan-shaped, dorsad and ventrad radiating portions
(the m. prceorbicularis dorsalis et ventralis). By loosening the
ligamentum it becomes plain that the posterior fascicles are traversing
ones, extending from above downwards in an arc inside
the ligamentum, and closely joining the orbicularis-fascicles. The
anterior fascicles, however, are interrupted; they arise separately
inside the lig. palpebrale. The dorsal ones cover most of the
origin of the m. nasolabialis, whereas the ventral ones partly interlace
between the fascicles of the latter (PI. 4).

The in. nasolabialis (PI. 1 and 4) is in front of the m. prse-
orbicularis. It intimately joins the m. prseorbicularis but still it
may be distinctly separated from it by dissection. It is a small
muscle composed of coarse fascicles with plenty of intramuscular
adipose connective tissue. It arises above and a little in front of
the orbit, partly from the frontal bone, partly from the fascia
that covers the portio superior m. maxillo-labialis. The origin is
mostly covered by the m. prseorbicularis dorsalis. The fascicles go
downwards in the shape of a fan; the posterior ones go almost
straight downwards in the direction of the angle of the mouth,

x) Studies in Comparative Anatomy. II. Anatomy of the Indian Elephant. London
1878. Reprinted from Journ. of Anat. and Physiol. Vol. 12—13.
2) Miall and Greenwood 1. c. p. 31.