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Elephant.

Buccinator-group. Lateralis nasi. Rectus nasi.

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Finally, the m. longitudinalis lateralis is mentioned. This is said
to consist of 2 portions: »one is derived from orbicularis oris,
the other springs from the anterior margin of the orbit. They
are inserted by a series of slips between the anterior and posterior
longitudinal muscle along the proximal half of the proboscis«.
One of these portions — the one that arises »from the anterior
margin of the orbit« — evidently corresponds to our portio inferior
m. maxillo-labialis; but what the other portion represents
we cannot imagine.

We have mentioned the investigations of the previous authors
in such detail to show the limited nature of their scope: It is a
merely descriptive treatment — moreover very deficient, and full
of mistakes — and not the least attempt has been made to establish
the morphology of the muscles of the trunk.

5. THE M. LATERALIS NASI

(PI. 3; PI. 14, fig. 11)

is powerfully developed, and consists of coarse fascicles with
plenty of adipose intramuscular connective tissue, so that the
fascicles may easily be dissected out singly. The origin of the
muscle forms a bow along the lateral and dorsal circumference
of the bony entrance to the cavity of the nose: and farther on
in the median line from the cartilaginous nose (septum). If we
begin at the lateral circumference, the anterior fascicles arise
from a firm and compact mass of connective tissue, in front of
the orbit, and covered by the m. maxillo-labialis. Farther up the
fascicles arise from the proc. nasalis of the intermaxillary bone
and from this point the line of origin turns on to the nasal
bone (PI. 14, fig. 11). The fascicles arising from the nasal bone
are separated by a space which was filled with adipose tissue
from those coming from the intermaxillary. The nasal fascicles
unite, like a fan, and are inserted into the mucous membrane
of the nose, whereas those from the intermaxillary run more
transversally inwards, and also are inserted into the mucous
membrane. The muscle proceeds farther down upon the cartilaginous
nose, where it arises, a little from the median line, forming
a flat, rather powerful muscular body; which with its
transverse fascicles covers the greatest part of the cartilaginous
wings of the nose, inserting themselves to the surface of these
wings near the margin. In front, in the median line, the right
and left muscular bodies unite so intimately that no limit can
be shown between them.

That the muscle described is the m. lateralis nasi is beyond
all doubt. The part thereof which arises from the lateral, and
dorsal circumference, of the bony entrance of the cavity of the
nose, and is inserted into the mucous membrane of the nose,
corresponds exactly to that which we have found in the other
Mammals examined. This part of the muscle is, in the Elephant,
uncommonly well developed, and evidently serves to pull the
soft nasal wall outwards, and, by this means, to increase the
space in the cavity of the nose at this spot. Thus then it is certainly
active when the animal drinks (sucks up the water into
the trunk).

The part of the muscle which lies on the cartilaginous wings
of the nose is somewhat different, in so far as its fibres do not
insert themselves into the mucous membrane of the nose itself;
but to the cartilaginous wings of the nose. The only one of the
Mammals examined by us in which we have found anything
similar, is the Horse (v. Appendix) where a rather powerful
muscle is stretched between the freely moveable cartilaginous
wings of the nose (the m. transversus nasi of the Veterinarians,
comp. PL 8, fig. 1). In our examination of the Horse we found
that this m. transversus nasi is nothing more than the anterior
part of the m. lateralis nasi, which has here lost its insertion
into the mucous membrane of the nose, and has become instead
inserted into the wings of the nose. The examination of the Elephant
fully confirms this view. The muscular body lying on the
wings of the nose is a direct continuation of the part of the m.
lateralis nasi that arises dorsad of the entrance to the nose. Between
the Horse and the Elephant there is, however, this difference
, that in the former, the fascicles run without interruption
from one wing of the nose over the median line to the other;
in the Elephant on the contrary this »m. transversus nasi« has

not been so much differentiated — or: it shows a more primitive
feature, as it still consists of a right and a left muscular
body each forming a direct continuation of the corresponding
m. lateralis nasi; only in front the two muscular bodies meet.

6. THE M. RECTUS NASI

(PI. 3; PI. 14, fig. 2, 5, 6, 7 and 8)

is immensely developed, and forms a powerful system of fascicles
that extend through the whole length of the trunk radiating outwards
from the whole circumference of the long nasal tube
(PL 14, fig. 2). In order to study more closely the details of the
arrangement of the fascicles of the whole of this system we have
used a series of transverse sections cut in different parts of the
trunk, from its very root outwards to its tip. The fascicles show
the following arrangement.

On a section (PL 14, fig. 5; comp. PL 3) immediately in front
of the cartilaginous nose there are seen fascicles which, from the
dorsal circumference of the nasal tube, radiate dorsad. The fascicles
are long, not very closely set, and directed a little obliquely,
dorso-distad; they are arranged in parallel longitudinal rows
ending in the connective tissue under the portio superior m.
maxillo-labialis. The spaces between them are filled with adipose
connective tissue. Mediad, they pass smoothly into short fascicles
that run transversely from one nasal tube to the other. These
transverse fascicles are found through the whole of the soft septum
between the nasal tubes, in which they lie arranged in small
groups separated by rather compact connective tissue. If the
dorsal fascicles are followed laterad, they are found to pass immediately
into a close mass of thick fascicles, which, from the
whole lateral circumference of the nasal tube radiate laterad.
These fascicles are arranged, fairly regularly, in transverse rows,
and project between the fascicles of the m. nasalis (PL 3). Proxi-
mad, these lateral fascicles border on the m. lateralis nasi, and
there is so smooth a passage between these two muscles that no
limit at all can be shown between them. If the lateral fascicles
are traced ventrad, they are found to be continued by fascicles,
that, from the whole ventral circumference of the nasal tube radiate
ventrad, and are inserted into the dorsal face of the intermaxillary
bone. These ventral fascicles are short, the distance
between the nasal tube and the dorsal face of the intermaxillary
being small.

In the next part of the trunk the nasal tube rises more and
more from the intermaxillary bone, and, on a section at the anterior
margin of this, the following is found (PL 14, fig. 6): Dorsad,
the fascicles radiate upwards, standing closer than in the section
first described; laterally they pass smoothly into the laterad radiating
fascicles, which thrust themselves out between the fascicles
of the m. nasalis. Finally there is found, ventrad, a high, and
thick mass of close standing fascicles which are inserted into
the intermaxillary bone. These fascicles border laterad onto the
m. nasalis and are so intimately annexed to them, that hardly
any limit can be shown. We cannot decide whether this intimate
cohesion of the rectus, and the nasalis, and the equal close connection
of the rectus and the lateralis nasi mentioned under the
description of the first section may be conceived of as demonstrating
a genetic connection between these muscles. In the Elephant
, where the fascicles are so coarse that each of them may
easily be dissected out, this cohesion is very conspicuous; but
we must admit that we have not sufficiently examined the relations
of these muscles in other Mammals, where the thinness of
the fascicles greatly impedes the examination. In itself, it is
by no means unlikely that the said muscles belonged to, or
were developed from, a common system; but the isolated observations
we have made do not justify any definite conclusion.
The more so, as we are here dealing with an animal whose
muscular system has in so many respects undergone most radical
changes. Indeed, there is the possibility as well, that the said
connection of the muscles is but of a mere secondary nature. —
On the section described, there are also transverse fascicles in
the septum between the nasal tubes. In about the dorsal half