The Denison review. [volume] (Denison, Iowa) 1867-current, 1903-06-24
THE ELEPHANTS TRUNK.
finals Present Fern Is the Re-
suit of Evolutiens

The recent discoveries of fossil re.
mains of ancestral proboscideans in
the tertiary deposits of the Fayum dis
trict in Egypt, combined with care
full study of the skeleton of certain
species of mastodon known to science
for many years, have ena bled DIR. c. w.
Andrews proceedings of the Royal
society to indicate very clearly the
manner in which the trunk of the mod
ern elephant has been gradually
evolved, says London Field.
The ancestral proboscideans were
comparatively small and short-legged
animals, which had, of course, no diff
ticulty in putting their mouths to the
ground. AS the successors of these
primitive forms gradually increased in
bodily stature, and more especially in
length of limb and size of head, 1t will
be obvious that in order to be able to
obtain food or water from the level Of
the ground they must either have in
creased the length of the neck or have
developed special prolongation of
the muzzle.
But in the case Of large and heavy
headed animals, whose successors were
destined to carry the enormous tusks
of the extinct mastodons and modern
elephants, it will be further manifest
that an increase in the length of the
vcrtebrae of the neck and hence of the
neck itself would, from mechanical
considerations, have been impossible.
Accordingly the only practicable
course was the elongation of the muz-
zle.
In the earlier forms the lower jaw
was short and heavy, with the union
between the two branches (symphy-
sis) very massive. On the other hand,
in many of the early mastodons the
lower jaw had become very long and
terminated in long troughlike SYM
physis. To accord with this prolonga-
ton of the lower jaw it is quite evident
that the upper lip and nose must like
wise have been elongated and they
probably formed kind of proboscis,
of which the lip was most likely more
or less prehensile.
For some reasons or other no sooner
had the prolongation of the lower jaw
attained it's maximum development
than the length of its troughlike SYM
physis began to diminish till the struc-
ture eliminated in the short snout
found in later mastodons and the mod
ern elephants. During these changes
the length of the proboscis must have
continued to increase, while its fexi-
bility and tactile power were likewise
at the same time augmented till the
structure attained its full develop
ment in the elephants of to-day.
In this connection it may be noticed
that the trunk of the African elephant
differs very markedly in structure
from that of it's Indian cousin, thus in
dicating that these two types diverged
from the common ancestral stock at a
comparatively early date. In addition
to the well-known difference in the
form of the tip the trunk of the Afri-
can elephant is distinguished from
that of the Indian species by its
segmented structure, so that it has the
appearance of being composed of a
number of distinct pieces, one of which
slides into the other, like the joints
of telescope, the Indian elephants
trunk, on the other hand, is uniformly
elastic throughout and may be COM
pared to taperlng india rubber hose
pipe. 1t is evidently a more highly
specialized structure than is the pro-
boscis of the African species.