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Elephant.

M. rectus nasi. Muscular system of the trunk.

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none were found, whereas they were numerous in the ventral
half. And, moreover, they proceed some distance down, ventrad
of the septum, where they partly thrust between, partly pass
into, the ventral fascicles.

The next section (PI. 14, fig. 7) is cut just in front of the
point of the under lip. The radiating fascicles are here seen in
the dorsal, lateral, and ventral circumference of the nasal tube.
The lateral and ventral ones are not present in quite so great a
number as in the second section, and the ventral ones have become
longer and run a little more curved ventrad. On the other
hand, it is to be noted that, in the space from the 2nd to the 3rd
section, a considerable increase of the transverse fascicles has
taken place. Through the whole height of the septum (which, however
, is not considerable in this place) these fascicles are found,
and we draw particular attention to the fact that they proceed
a considerable distance down, below the nasal tubes, where they
form a close mass of thick, transverse fascicles, which, with their
ends somewhat turn in a bow, upwards, ending in the connective
tissue inside the ventral radial fascicles.

Finally, we come to a section about the middle of the trunk
(PI. 14, fig. 8): Here we see the radial fascicles from the dorsal,
lateral, and ventral circumference of the nasal tube as a continuous
, radiating, muscular mass. The ventral fascicles are here
not much longer than the dorsal ones. Through the septum, and
below it, the transverse fascicles are found. In the septum itself,
they are numerous, whereas much fewer are found below it than
in the former section. This likeness in the main appears again
in the sections throughout the distal half of the trunk; the fascicles
, however, gradually decreasing more and more in length.

We must yet add that we have not contented ourselves with
simply cutting through the trunk in the places described, but
have in reality made a great number of sections throughout
its whole length. By this means we have found that the transition
from the likeness offered by one section to that offered by
another is quite gradual.

Now, if by means of the sections described, we try to form
one picture of the whole m. rectus nasi the result will be as follows
: Through the whole length of the trunk there is a large
system of radial fascicles. They arise from the mucous membrane
of the nasal tube radiating thence dorsad, laterad, and ventrad.
The dorsal and ventral fascicles bend into the septum, and run
here from one nasal tube to the other. In the details there is
some variation in the length and more or less close arrangement
of the fascicles; this is especially the case with the proximal half
of the trunk and is evidently in close connection partly with
the alteration of the form of the lumen of the nasal tube partly
with its situation in the section, and partly with the relations of
the trunk to the neighbouring parts. As to the last it must especially
be remarked that the ventral fascicles, in the space where
the trunk overlies the intermaxillary bone, insert into the bone,
which is not otherwise the case with the rectus nasi generally.
Further it must be remarked that from about the anterior margin
of the intermaxillary bone and farther down through the
rest of the trunk the transverse fascicles proceed down in the
portion below the nasal tubes and are particularly numerous in
the proximal part of the trunk.

As to the insertion of the fibres we see in the sections that
the dorsal and lateral fibres pass into thin, short tendons that
thrust up between the fascicles of the m. maxillo-labialis (PI. 14,
fig. 2) and insert themselves into the deep face of the fascia outside
this muscle. The ventral fascicles of the basal part of the
trunk are inserted, as described, into the intermaxillary bone. On
the rest of the trunk by far the greater number end in the connective
tissue inside the portio supralabialis, whereas a smaller
number may be followed somewhat outwards into the connective
tissue between the fascicles of this muscle (PI. 14, fig. 2).

Further, our examinations show that the rectus-fascicles are
arranged very regularly in longitudinal rows, separated from
each other by adipose connective tissue. On the whole dorsal
and lateral circumference of the trunk — that is, in the whole
extent of the m. maxillo-labialis — these rows of fibres pass into

low aponeuroses that extend up through the m. maxillo-labialis
(PI. 2) and so become inserted into the fascia — the thin short
tendons mentioned above in the description of the section being in
reality aponeuroses, each aponeurosis being common for one row
of fascicles. We have already described these aponeuroses in
full detail, when dealing with the m. maxillo-labialis. And what
is said of their arrangement, and course, also applies to the rows
of fibres. Here we have only one addition to make: Between the
rows of the fibres with their aponeuroses grooves are formed;
about the inner half of each of these groves is filled with adipose
tissue, so that only a little more than the outer half is occupied
by the fascicles of the m. maxillo-labialis (PI. 14, fig. 2).

The previous authors (v.e.g. Miall and Greenwood, Harrison1),
Watson) have, of course, all seen the radial fascicles; but as to
the examination, and description thereof it is as with their description
of the buccinator group: most deficient.

If we survey the whole muscular system of the trunk, we
find it contains, first longitudinal and oblique fascicles, the latter
moreover arranged in two crossing layers. The longitudinal fascicles
, m. maxillo-labialis, occupy the dorso-lateral circumference;
the oblique fascicles, the pars rimana and the pars supralabialis
m. buccinatorii, the ventro-lateral. In this arrangement of the fascicles
lies the explanation of the extremely free mobility of the
trunk. The longitudinal muscles, »the levatores proboscidis« of
previous authors, produce the raising movements of the trunk,
the amplitude of which, as is well known, is so great that the
trunk may be raised up so as to rest upon the upper surface of
the head and the neck. This movement is, in the main, made
by the portio superior m. maxillo-labialis, whereas a onesided
contraction of the portio inferior, which lies chiefly on the lateral
face of the trunk, will produce a lateral motion. A simultaneous
activity of the oblique muscles, the »depressores pro-
boscidis« of previous authors, will produce either a lowering of
the trunk, or, (by simultaneous relaxation of the longitudinal
muscles) the well-known rolling up thereof against its ventral
face, whereas a onesided contraction will evidently be instrumental
in the lateral motion. By a combination of these movements
the trunk will be able to adjust itself in all directions.
For the sake of comparison we may invite attention, for a moment
to the muscles of the tail of Mammals, which it is hardly
necessary to remind our readers, is also most freely movable.
The muscles of this organ are most familiar in the domestic
Mammals, where they are, primarily, arranged longitudinally,
both on the dorsal and the ventral faces: and these muscles first
produce the raising and depressing movements. The former may
be carried so far that the tail is rolled up against its dorsal
face2), but these longitudinal fascicles can also, certainly by onesided
activity, — eventually supported by the small mm. inter-
transversarii that span from one proc. transversus to the next —
produce lateral motions. But these are, in the main, due to a
pair of oblique muscles that, one on each side, extend from the
pelvis to the anterior vertebrae of the tail (the m. coccygeus of
the Veterinarians). The tail then, can execute many of the same
movements which we have described in the proboscis: but in
the more special arrangement of the muscles there is however
an essential difference. The muscular mass, the fleshy mass, is
in the tail chiefly gathered round its »root«, i. e. its proximal
part; certainly the muscles extend for a considerable distance
down the tail (some muscles almost to its very point), but distad
the fleshy mass soon greatly decreases. The great range of movement
of which the tail is capable, is then produced in such a
way that from the muscular mass there arise long thin tendons
that run far out on the tail, often passing over several vertebrae
before they are inserted. On the proboscis the case is otherwise.
The fleshy mass here extends to its very tip, being the chief
content of the proboscis, which by its immense contents of fibres,
can throw enormous force into its motions.

*) The paper quoted p. 43.

2) There are, however, also Mammals that can roll up the tail against the
ventral face.