31 
Elephant. 
M. maxillo-labialis. 
32 
much greater space for traverses than is the case in the Elephant, 
in which the muscle has become so narrow. That the maxillo- 
labialis in the Elephant has been developed in a manner rather 
different from that found in other Mammals is not surprising. 
The portio inferior radiating like a fan in other Mammals (vide e. 
g. the figures of Halmaturus, Horse, Dromedary, Tapir) has in the 
Elephant become a long narrow muscle, whereas, on the other hand, 
the portio superior has been developed into a powerful muscle, 
which has widened its origin to the very median line and po¬ 
steriorly all over the fronto-nasal-region. It has been developed 
into an enormously powerful raising muscle for the trunk, a 
»m. levator proboscidis«, by which name all previous authors 
have treated this muscle without, however, trying in the least to 
explain its morphology. Such was also the case with the portio 
inferior which only was put down as a »lateral, longitudinal 
muscle* (vide e. g. Miall). 
The longitudinal muscular system formed by the maxillo- 
labialis on the dorsal and parti}' on the lateral circumference of 
the trunk is, as is known, able to develop an enormous force, 
just as it also has a considerable extent of motion, the trunk of 
the Elephant possessing a wonderful mobility. The working po¬ 
wers of a muscle are to a large extent determined partly by the 
number of muscular fibres it contains, partly by the length of 
the muscular belly; the former factor determines the force which 
the muscle is able to develop, the latter, however, the extent of 
its motion. In conformity to this the m. maxillo-labialis has in 
the Elephant obtained an enormous length and a considerable 
bulk of muscular fibres, which are to a large extent arranged in 
a most singular manner, quite different from that of the muscle 
in other Mammals. 
The particulai’s in the structure of the muscle are as fol¬ 
lows (comp. PI. 1 and 2). It is very coarse-fibred and in its whole 
course along the trunk is covered by a very strong fascia (PL 4, 
where the fascia is dissected off on the proximal part of the 
muscle), which, on the proximal part of the trunk is separated 
from the corium by a layer of loose subcutaneus connective tis¬ 
sue, so that the skin may here easily be taken off. But very 
soon (about the end of the upper fourth of the trunk) the sub¬ 
cutaneous connective tissue begins to be reduced and it soon 
disappears, so that the corium throughout a very considerable 
length of the organ (more than the half) is intimately united 
with the fascia and cannot be separated from it. Posteriorly the 
fascia proceeds on to the face, where it covers the proximal 
part of the portio superior; here it gradually grows thin¬ 
ner and is at last lost in the connective tissue on the frontal 
surface. 
In the proximal part of the portio superior, that is the part 
thereof which extends across the nasal cartilage with its muscles, 
from which the portio superior is separated by a layer of adi¬ 
pose tissue, — the intramuscular connective tissue is very power¬ 
fully developed, and forms thin fibrous longitudinal leaves, 
which extend upwards through the muscular body between the 
bundles and insert into the inner face of the fascia. Between 
these leaves there are deep grooves or rather canals, being clo¬ 
sed above by the fascia, each of them quite filled up with coarse 
fascicles. 
In front of the cartilaginous nose where the portio superior 
passes out upon the trunk these fibrous intramuscular leaves 
proceed in the fibrous leaves that belong to the radiate muscular 
system of the trunk (v. Plate 2 and PI. 14, fig. 2). As we shall 
describe more fully below, there is in the trunk a considerable 
system of muscular bundles that, from the wall of the nasal 
canals, radiate upwards. They are arranged in long parallel rows 
and each such row passes into a thin fibrous leaf that is inserted 
into the inner face of the fascia. Between these rows of radiate 
muscular bundles with their fibrous leaves, there are formed 
long grooves or canals, in which the fascicles of both portions 
of the maxillo-labialis are placed, similar to the grooves limited 
by the leaves of the intramuscular connective tissue in the proxi¬ 
mal part of the portio superior; the grooves on the trunk are 
deepest on its proximal part (some of the deepest grooves mea¬ 
sured iy 2 — 2 cm in height and were 1—1 % cm broad just be¬ 
low the fascia), whereas they gradually grow lower and narrower 
towards the distal end of the trunk. 
These leaves present many special peculiarities (fig. D). Some 
of them are of considerable length, and may be traced far down 
the trunk with long intervening grooves; but no leaf reaches 
continuously from the upper end of the trunk to the lower one. 
Other leaves are short (vide e. g. a and b in fig. D), some of the 
shortest we found measured 2—3 cm. Now, if we follow such 
leaves it is found that they suddenly stop with steep, truncated 
ends (v. a in fig. D). At a shorter or longer distance distad of 
this, one or two new leaves begin (v. b in fig. D) which may 
then be traced for a shorter or longer extent. Hereby there arise 
many singularities in the course of the grooves. If we follow a 
groove (vide e. g. the grooves 7, 15, 17, 22, 23, 24 in the fig. D) 
then, after a shorter or longer course we suddenly meet a leaf 
that arises from the trough of the groove and at the sharp edge 
of which the groove, as it were, splits into two. Sometimes this 
is repeated several times in the course of a groove (v. e. g. the 
grooves 7, 15, 17 in the fig. D) so that it is divided into several 
parallel grooves. Sometimes we see how a groove splitting into 
two by a leaf that juts out from its bottom, reunites at the 
distal end of this leaf (v. e. g. the groove 7; the upper ti). Be¬ 
sides these peculiarities, determined by the length of the leaves, 
and by their origin, there are others which arise by the forma¬ 
tion of abundant »anastomoses« between the leaves. The leaves 
unite or amalgamate; and in details this is done in several ways. 
Very frequently two leaves are found approaching each other, 
uniting for a short space then parting again (vide e. g. the grooves 
I, 2, 6, 8, 10, 13, 16, 17, 23). The groove is in this way inter¬ 
rupted and at the »anastomoses« the two leaves are firmly con¬ 
nected by short, tight fascicles of connective tissue. Sometimes 
this is repeated several times in the course of a leaf so that it 
»anastomoses« now with its mediad now with its laterad neigh¬ 
bouring leaf (v. e. g. the plate between the grooves 1 and 2). In 
other places there will be found two (v. e. g. the grooves 5, 11, 
14, 15, 17, 24) or three leaves (v. the grooves 21—22) amalga¬ 
mating so that the intervening groove or grooves are closed. 
Most frequently this form of »anastomoses« appears at the short 
leaves, most of which join the long neighbouring leaves, but it 
is also found now and then between the latter (v. e. g. the grooves 
II, 24). The leaf formed by the anastomose then proceeds in 
order to divide after a shorter or longer course (v. the grooves 
15, 21) and to anastomose again etc. Upon the whole, there will 
very frequently be found divisions of leaves, often in such a 
manner that from the lateral faces of a leaf others arise which 
generally stop after a shorter or longer course parallel to the leaf 
of origin (v. e. g. the grooves 7, 15, 17); it looks as if a second¬ 
ary, proximally closed groove had, as it were, been cut off from 
the main-groove, reuniting the latter at the distal end of the se¬ 
condary leaf. 
On the dorsal face of the trunk and on the neighbouring 
parts of its lateral circumference there is formed in this way a 
system of longitudinal fibrous, or muscular-fibrous leaves radi¬ 
ating through the wall of the trunk. Between them they include 
grooves, in the course of which, however, many peculiarities 
occur, brought about by the relations of the leaves mentioned 
above. In these grooves the muscular portion of the maxillo-labi¬ 
alis is imbedded, and so it becomes evident that an extremely 
large surface of origin and insertion is afforded the muscle 
by this arrangement, the leaves serving as surfaces for attach¬ 
ment. 
By the whole system of the radiate leaves the muscular body 
is, as it were, divided into parallel, longitudinal sections each 
consisting of a greater or smaller number of coarse bundles, 
which may most easily be dissected and followed along their 
whole length. The length of such sections differs considerably. 
We found them up to 12—15 cm long. The proximal sections arise 
from the aponeurosis on the nasal surface and project into the 
grooves, where they show the following insertions: Some fascicles 
end in short tendons, from the distal ends of which new fascicles 
