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Elephant.

Ear-muscles. Musculus x.

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an aponeurosis ensheathing the m. temporo-auricularis (No. 13);
but the inferior bundles take their origin from the skull close
in front of and above the so-called external bony auditory meatus
(formed by the squamosal bone and surrounding partly the
proximal end of the auricular cartilage). The inferior bundles
are horizontal, the superior vertical; the inferior part of the
muscle is far the strongest, the superior being rather thin. The
insertion is on the distal border of the tragus and on the bridgelike
part of the auricle lying between the incisura post. 4 and
the incisura ant. 2.

From the hinder end of the zygoma arises a strong rectangular
muscle (No. 12), which is inserted into the auricle below
the muscle just described, on the mediad side of the auricle
unto the margin, which in an ordinary Mammal is the posterior
margin of the ear-conch (distal border of incisura post. 4). The
insertion quite corresponds to that of the auricular portion of the
m. sphincter profundus. Against this homologization stands the
direction of the fibres, which is horizontal, and the fact, that
they take their origin from the zygoma. But the altered direction
of the fibres may be a consequence of the torsion of the
whole ear. And as to the origin of the muscle from the zygoma
it must be remembered that other facial muscles may also sometimes
take their origin from the connective tissue or from other
muscles, sometimes from the skeleton. And as to the sphincter
profundus especially we have seen that it may arise from the
anterior end of the sternum (e. g. Myopotamus, p. 8). So far
there is nothing which could make it impossible to accept that
interpretation.

The only other possibility is that it is a muscle comparable
to the »adductor externus« of the Horse, which muscle we have
interpreted as a separate portion of the adductor inferior. But
this muscle is a development peculiar to the Horse, and not present
in other Mammals examined by us. And it appears not very
probable that the muscle in question, in the Elephant, should also
be a separate part of the adductor inferior. But it is possible, and
the question as to the homology of the muscle is still an open one.

c. Musculus temporo-auricularis (No. 13).

This muscle takes its origin from the skull close above the
external bony auditory meatus. In comparison with the same
muscle in most other Mammals it is a rather short, and stout,
muscle. It is inserted, as usual, into the anteron 5. The muscle

is in the Elephant situated as in the Dog on the front side of
the cartilaginous meatus, while for instance in the Horse it has
its place more posteriorly. In the Elephant it is situated nearer
to the outer surface than in other Mammals, so that it is partly
visible as soon as the skin is removed; in other Mammals it
lies deeper.

d. Muscles which both arise from and are inserted into

the auricular cartilage.

The m. anted sexti (No. 14) has its place directly behind the
adductor inferior, with whose superior fascicles it is intimately
connected. It arises (as in the Horse etc.) from the tragus and
does not as in most other Mammals reach the anteron 7 but is
inserted into the outer side of the hooked anteron 6 (comp. the
Horse, p. 19). It is a rather strong, slender muscle.

The m. transversus (No. 15) has, as usual, its place on the
mediad side of the auricle; it is comparatively strong. Most of
its fibres have a direction toward the apex of the ear; the fibres
of a smaller anterior portion (No. 15*) are directed toward the
superior (anterior) margin of the ear.

Note. Finally we note a little rather singular muscle, which
we have found in the Elephant examined: Musculus x, Plate 2.

After removal of the auricle and its muscles we found on
the upper part of the right side of the head, directly behind the
temporal fossa, a triangular pennate muscle, thin and flat. The
muscular body, which is 5 cm broad, 7 cm long, is at the top
continued into a narrow tendon, which has a dorsad direction
and ends in the periost behind the temporal fossa. The muscular
fascicles radiate downwards and end in the connective tissue.
The muscle lies on a considerable layer of adipose tissue, a couple
of cm thick, lying outside the skull between the origin of the
m. temporalis and the insertion of the m. splenius.

This remarkable muscle was only present on the right side
of the head; on the left side there was no trace of it; we note
especially, that on the right side it was so distinct and conspicuous
, that there is no possibility of our having overseen it on
the left side, if it had been present there. How this muscle shall
be interpreted, how it has arisen, and what are its functions,
we are at a loss to say. It has no connection whatever with the
ear-muscles, nor with any of the other muscles, nor have we in
other Mammals found a muscle comparable with it.