35 
Elephant. 
Buccinator-group. 
36 
the mandibular portion described; where the latter forms the 
transverse layer that is by a layer of connective tissue distinctly 
separated from the underlying longitudinal fascicles, whereas in 
the lower half of the buccinator the longitudinal fascicles of the 
maxillary portion, quite closely, and without any limit whatever, 
join those of the mandibular portion. Thus the buccinator, in 
its upper half, consists of two distinctly separated layers: a su¬ 
perficial transverse layer, and a deep longitudinal layer, — in its 
lower one, however, only of a longitudinal layer (comp. PI. 16, 
fig. 16). As to the longitudinal fascicles in the maxillary portion 
it must however be remarked that they together form a rather con¬ 
siderable mass as under their course numerous new fascicles are 
added, arising, partly from the maxillary bone, and partly from the 
external surface of the mucous membrane. The latter forms a 
large and somewhat oblique fold (PL 3) which juts far out being- 
on both surfaces used partly as insertion partly as origin of num¬ 
bers of the deep longitudinal fascicles of the buccinator. 
The deep »longitudinal layer* of the buccinator, — that is, 
the longitudinal fascicles belonging to the maxillary portion — 
proceeds onwards as well in the upper as in the under lip for¬ 
ming, immediately under the skin, a brim of fascicles that run 
longitudinally through the lips: pars rimana (in PI. 4 this brim is 
seen in the upper lip; in the under lip it is only visible posteriorly 
as the upper lip projects so far to the side that it covers the 
upper part of the under lip). 
If we first examine the under lip, we see, in PI. 4, the lower 
part of the deep longitudinal fascicles projecting in rather a con¬ 
siderable number partly under, partly between, the fascicles of 
the transverse layer, after which they bend obliquely downwards 
in the under lip ending here with short pointed tendons, inserted 
to the skin. The fascicles, however, reach only a short way — 
a few centimeters — into the under lip; but at the same time 
new fascicles have been added arising below the angle of the 
mouth (PI. 16, fig. 16). The new fascicles run onwards in the un¬ 
der lip, at first mixed up among the fascicles of the buccinator, 
and where the latter end the new ones continue their course for¬ 
wards as an immediate continuation thereof. The new fascicles 
extend, for a shorter or longer distance, forwards into the lip, 
but as they end, other fascicles are added, which continue the 
course farther on. In this way there is formed a continuous 
brim — 1 or l'/ 2 cm high, — of longitudinal fascicles which 
may be followed forwards to about the base of the free spout-like 
termination of the under lip where the fascicles end, at the same 
time spreading somewhat. 
The upper fascicles of the deep longitudinal layer of the 
buccinator proceed above the angle of the mouth into the upper 
lip (PL 4), where, after a short course, they end with short 
pointed tendons and in a way similar to that which obtains in 
the under lip: new fascicles are added forming an immediate 
continuation of the fascicles of the buccinator. In this way there 
is formed a continuous border of longitudinal fascicles, but in 
the upper lip they are present in far greater numbers than in 
the under lip, so that the border becomes much broader; it, how¬ 
ever, is not very thick. The fascicles reach down to the free 
margin of the upper lip, running in a bow corresponding to the 
form of the lip; they proceed outside the fold around the incisor 
reaching in front thereof out upon the trunk, where they con¬ 
tinue their course down to its very point, forming a superficial 
muscular layer on its ventral, and partly its lateral face (PL 1, 
comp. PL 16, fig. 16). 
Before we follow the further course of the buccinator upon 
the trunk we will compare the part already described with the 
buccinator in the other Mammals examined, as is mentioned 
in the General Part. We find then in the Elephant the two 
layers generally found, a superficial transverse layer and a longi¬ 
tudinal layer, which posteriorly at the origin pass so closely 
into each other that they only form one layer. We have found 
the same in several Ungulates (Tapir, Horse, Boar, Wapiti, Elk, 
Zebu), and in several figures (PL 8, fig. 1 and the schemes PL 16, 
fig. 1—15) the details of the relations of the fascicles to each 
other are given. A comparison shows then that the state of 
things in the Elephant recalls most nearly that found in the Pig 
(PL 16, fig. 15); ventral longitudinal fascicles gradually taking the 
transverse direction. In the Elephant, however, the transverse 
layer is rather considerably reduced; it only occupies about the 
upper half of the buccinator, whereas in return the longitudinal 
laj^er, which owing to the reduction of the transverse layer lies 
superficially on about the lower half of the buccinator, is by far 
the more important and powerful. Indeed, it is probable that the 
reduction is in a close connection with the peculiar form of the 
cheek in the Elephant. For the cheek is short and — what must 
be particularly emphasized — high, and has rather a considerable 
mass (mucous membrane, glands, muscles, connective tissue) 
so that the fascicles of the transverse layer run in a great arc 
over the glands and the longitudinal fascicles; so the buccinator 
will certainly most easily be able to perform its chief function — 
that is, to hold the food in between the grinding surfaces of the 
molars during the mastication — by means of longitudinal fas¬ 
cicles. We shall in this respect also refer to the buccinator of 
the Dog (v. the General Part p. 27 and comp. PL 16, fig. 17) in 
which animal the cheek, as is known, also is very short; here the 
transverse layer is reduced too since only the pars rimana re¬ 
mains, whereas all the rest, the fascicles extending from upper 
to lower jaw, is wanting. — By the reduction of the transverse 
layer in the Elephant its share in the formation of the pars ri¬ 
mana has also suffered; indeed the layer proceeds a short distance 
into the upper lip but its fascicles have the same direction as in 
the cheek and does not bend round the angle of the mouth as 
is the case in other Mammals. So the pars rimana in the Ele¬ 
phant is exclusively formed by the longitudinal layer of the buc¬ 
cinator. That it is really the pars rimana which is found in the 
lips we think may be concluded from the fact that the longitu¬ 
dinal layer of the buccinator in several other Mammals may also 
contribute to the formation of the pars rimana (Wapiti, Zebu, 
Swine, Erinaceus, Rabbit). 
As we have said, the pars rimana proceeds down upon the 
trunk throughout its whole length. The origin of the fascicles 
proceeds, in front of the incisor, from the skin of the fold of the 
upper lip round the tooth, upon the ventral face of the root of 
the trunk. On the trunk the fascicles arise from a rather power¬ 
ful aponeurosis which covers its ventral face. On the proximal 
part of the trunk it may be rather easily separated from the skin 
as there is a thin layer of subcutaneous connective tissue; but 
distad this layer is gradually reduced, so that the aponeurosis 
is here closely united with the corium and onlv with difficulty 
may be dissected out. The line of origin of the fascicles is on 
the upper half of the trunk only a short distance from the me¬ 
dian line, but under its further course it turns gradually more 
and more laterad, reaching, on the distal part of the trunk, out 
to the very lateral margin of the ventral face 1 ); a broader and 
broader piece of the ventral face of the trunk is therefore covered 
by the aponeurosis (PL 14, fig. 9). From the whole of the margin 
of the aponeurosis the fascicles arise and form a continuous su¬ 
perficial layer in which the fascicles run obliquely distad and 
dorsad, lying on the ventral and partly on the lateral circum¬ 
ference of the trunk (PL 1). On the proximal part of the trunk, 
where the fascicles are thick and coarse, they run rather steeply 
dorsad so that they soon turn from the ventral on to the lateral 
face (PL 4), but the farther one gets out upon the trunk the 
more they take the direction obliquely forwards and on the most 
distal part even so much that they almost become longitudinal. 
The fascicles are inserted into the fascia, which covers the max- 
illo-labialis; and upon the proximal end of the trunk, where the 
fascia and the skin may easily be separated, this insertion into 
the fascia is easily demonstrated (PL 4); but farther distad, 
where the fascia and the corium melt together, the fascicles are 
2 ) As long as the trunk is still covered with skin it has, — most distinctly on 
its distal part — as is well known, an almost level ventral face, which, on each 
side, by rather a projecting, notched, and fairly sharp edge is separated from the 
smoothly arched dorso-lateral face; this outer relief is chiefly called forth by the 
skin, whereas the muscles — and particularly the pars rimana — only slightly 
contributes to this. When the skin is dissected off, the trunk assumes a more 
cylindric or rather conical form. 
