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Descent of Man [ 1871]

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Author Topic: Descent of Man [ 1871]  (Read 4925 times)
Bullseye
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« on: February 09, 2009, 02:37:29 am »

The celebrated sculptor, Mr. Woolner, informs me of one little
peculiarity in the external ear, which he has often observed both in
men and women, and of which he perceived the full significance. His
attention was first called to the subject whilst at work on his figure
of Puck, to which he had given pointed ears. He was thus led to
examine the ears of various monkeys, and subsequently more carefully
those of man. The peculiarity consists in a little blunt point,
projecting from the inwardly folded margin, or helix. When present, it
is developed at birth, and according to Prof. Ludwig Meyer, more
frequently in man than in woman. Mr. Woolner made an exact model of
one such case, and sent me the accompanying drawing (see fig. 2).
These points not only project inwards towards the centre of the ear,
but often a little outwards from its plane, so as to be visible when
the head is viewed from directly in front or behind. They are variable
in size, and somewhat in position, standing either a little higher
or lower; and they sometimes occur on one ear and not on the other.
They are not confined to mankind, for I observed a case in one of
the spider-monkeys (Ateles beelzebuth) in our Zoological Gardens;
and Mr. E. Ray Lankester informs me of another case in a chimpanzee in
the gardens at Hamburg. The helix obviously consists of the extreme
margin of the ear folded inwards; and this folding appears to be in
some manner connected with the whole external ear being permanently
pressed backwards. In many monkeys, which do not stand high in the
order, as baboons and some species of Macacus,* the upper portion of
the ear is slightly pointed, and the margin is not at all folded
inwards; but if the margin were to be thus folded, a slight point
would necessarily project inwards towards the centre, and probably a
little outwards from the plane of the ear; and this I believe to be
their origin in many cases. On the other hand, Prof. L. Meyer, in an
able paper recently published,*(2) maintains that the whole case is
one of mere variability; and that the projections are not real ones,
but are due to the internal cartilage on each side of the points not
having been fully developed. I am quite ready to admit that this is
the correct explanation in many instances, as in those figured by
Prof. Meyer, in which there are several minute points, or the whole
margin is sinuous. I have myself seen, through the kindness of Dr.
L. Down, the ear of a microcephalus idiot, on which there is a
projection on the outside of the helix, and not on the inward folded
edge, so that this point can have no relation to a former apex of
the ear. Nevertheless in some cases, my original view, that the points
are vestiges of the tips of formerly erect and pointed ears, still
seems to me probable. I think so from the frequency of their
occurrence, and from the general correspondence in position with
that of the tip of a pointed ear. In one case, of which a photograph
has been sent me, the projection is so large, that supposing, in
accordance with Prof. Meyer's view, the ear to be made perfect by
the equal development of the cartilage throughout the whole extent
of the margin, it would have covered fully one-third of the whole ear.
Two cases have been communicated to me, one in North America, and
the other in England, in which the upper margin is not at all folded
inwards, but is pointed, so that it closely resembles the pointed
ear of an ordinary quadruped in outline. In one of these cases,
which was that of a young child, the father compared the ear with
the drawing which I have given*(3) of the ear of a monkey, the
Cynopithecus niger, and says that their outlines are closely
similar. If, in these two cases, the margin had been folded inwards in
the normal manner, an inward projection must have been formed. I may
add that in two other cases the outline still remains somewhat
pointed, although the margin of the upper part of the ear is
normally folded inwards- in one of them, however, very narrowly. The
following woodcut (see fig. 3) is an accurate copy of a photograph
of the foetus of an orang (kindly sent me by Dr. Nitsche), in which it
may be seen how different the pointed outline of the ear is at this
period from its adult condition, when it bears a close general
resemblance to that of man. It is evident that the folding over of the
tip of such an ear, unless it chang greatly during its further
development, would give rise to a point projecting inwards. On the
whole, it still seems to me probable that the points in question are
in some cases, both in man and apes, vestiges of a former condition.

  * See also some remarks, and the drawings of the ears of the
Lemuroidea, in Messrs. Murie and Mivart's excellent paper in
Transactions of the Zoological Society, vol. vii., 1869, pp. 6 and 90.
  *(2) Uber das Darwin'sche Spitzohr," Archiv fur Path. Anst. und
Phys., 1871, p. 485.
  *(3) The Expression of the Emotions, p. 136.

  The nictitating membrane, or third eyelid, with its accessory
muscles and other structures, is especially well developed in birds,
and is of much functional importance to them, as it can be rapidly
drawn across the whole eyeball. It is found in some reptiles and
amphibians, and in certain fishes, as in sharks. It is fairly well
developed in the two lower divisions of the mammalian series,
namely, in the Monotremata and marsupials, and in some few of the
higher mammals, as in the walrus. But in man, the Quadrumana, and most
other mammals, it exists, as is admitted by all anatomists, as a
mere rudiment, called the semilunar fold.*

  * Muller's Elements of Physiology, Eng. translat., 1842, vol. ii.,
p. 1117. Owen, Anatomy of Vertebrates, vol. iii., p. 260; ibid., on
the walrus, Proceedings of the Zoological Society, November 8, 1854.
See also R. Knox, Great Artists and Anatomists, p. 106. This
rudiment apparently is somewhat larger in Negroes and Australians than
in Europeans, see Carl Vogt, Lectures on Man, Eng. translat., p. 129.
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