71 
Appendix. 
Facial muscles of Tapir. 
Horse. 
72 
nose throughout the whole length of the trunk. They are most 
numerous and closest in the ventral and medial circumference 
of the nasal tube whereas they are more scattered dorsally and 
laterally, where they radiate out through a thick layer of numer¬ 
ous, small lobulate glands. Also medially and ventrally there are 
a number of glands imbedded between the fascicles of the rectus, 
but by no means so numerous as in the dorso-lateral circum¬ 
ference. If the fascicles are followed along the periphery of the 
nasal tube the following facts can be made out: Dorsally they are, 
as we have remarked, rather scattered, thrusting up between the 
glands and inserting themselves into the skin; farther down, 
laterally, they are seen radiating out between the glands, then 
thrusting out between the fascicles of the m. naso- and maxillo- 
labialis, which in this part of the trunk only forms a thin layer 
(PI. 14, fig. 3), finally to be inserted into the skin. The fascicles 
turn quite smoothly down to the ventral circumference of the 
nasal tube. If the ventral fascicles are followed through the 
whole length of the trunk, we find that, on the proximal por¬ 
tion, where the trunk ventrally borders on the intermaxillary and 
maxillary bones, they are short and rather scattered, separated 
from each other through rather plentiful connective adipose tissue. 
Distad they increase in number and length forming, on rather 
more than the distal half of the trunk, a thick mass of close 
thin fibres. Some of the outmost of these, having first, near the 
mucous membrane, the same direction as the rest, viz. dorso- 
ventrad, take a transverse direction and form a horizontal mus¬ 
cular layer (PI. 14, fig. 3, b ) below the rest and above a large 
ventral glandular mass. Others of the ventral rectus-nasi fascicles 
(PI. 14, fig. 3, a) have an oblique direction and run obliquely 
through the lateral longitudinal muscular sheath of the trunk 
consisting of the pars rimana, m. nasolabialis and m. maxillo- 
labialis. — If the dorsal fascicles are followed mediad, they turn, 
almost imperceptibly altering their direction, down into the sep¬ 
tum between the nasal tubes, here running transversely from 
one nasal tube to the other. Proximad they are somewhat scat¬ 
tered but soon increase rather considerably in number distad, 
so that the}' form a close layer of transverse fascicles through 
the septum. 
As to the rectus-bundles of the upper lip we find a continu¬ 
ous layer thereof going from the horizontal layer of rectus-bund¬ 
les described above into the lateral margin of the proboscis, the 
tips of the fascicles extending into the pars rimana (PI. 8, fig. 2 
and PI. 14, fig. 3, c). 
In the lower lip there are also rectus-bundles, traversing the 
lip from the mucous to the cutaneous side. 
7. HORSE. 
As to the facial muscles of the Horse we shall here mention 
only a few facts that are of particular interest for the investiga¬ 
tions in hand; otherwise referring to the accounts given in Ve- 
terinary-anatomical treatises. 
i. Platysma-sphincter-group. 
The sphincter superficialis does not reach the head. 
The platysma (= the m. cutaneus labiorum of the Veterinary 
anatomy) arises from an aponeurosis from the occiput. The lower 
part of the platysma forms a narrow, more or less continuous 
muscular layer that proceeds towards the angle of the mouth, 
where the fascicles are interwoven in the buccinator. The upper 
part, which radiates over the masseter, shows great variations in 
its development; now forming a rather continuous muscular body, 
and now represented only by scattered fascicles. 
The pars zygomatica is completely separated from the pla¬ 
tysma. 
The sphincter profundus. Of this, the portio auricularis (= the 
m. auricularis inferior of the Veterinary anatomy) is present. As 
to the portio palpebralis we are not quite sure if the m. malaris 
of the Veterinarians (PL 8, fig. 1) is this muscle. There is con¬ 
stantly found a thin, flat muscle that extends from the crista 
facialis, where it arises from the fascia, obliquely upwards and 
backwards to the lower eyelid; this direction of the fascicles, 
indeed, is different from that which we have otherwise found in 
the portio palpebralis; but on the other hand this muscle can 
hardly be considered as belonging to the orbicularis-group. 
2. Orbicularis-oculi-group. 
PI. 16, fig. 26; PI. 8, fig. 1. 
The m. orbicularis oculi consists of circular fascicles. There 
is a m. prceorbicularis, whose dorsal portion is continued poste¬ 
riorly by a large m. supraorbicularis extending upon the frontal 
surface (the m. corrugator supercilii of the Veterinary anatomy). 
As to the m. postorbicularis we have found two small portions of 
slanting fascicles that closely join the orbicular fascicles in the 
upper and lower eyelid. 
The muscular body of the m. nasolabicdis is frequently quite 
separated from the m. orbicularis; only now and then it reaches 
so far back that it immediately joins the m. prseorbicularis. The 
whole of the inferior part of the m. maxillo-labialis breaks through 
the m. nasolabialis so that the latter is, anteriorly, split into a 
superficial and a deep (resp. a ventral and a dorsal) portion. 
3. M. maxillo-labialis 
(PI. 8, fig. 1.) 
is, as in the Tapir, divided into two independent muscles; the 
upper portion (the m. levator labii sup. propr, of the Veterinary 
anatomy) being quite separated from the lower portion (the m. 
caninus of the Veterinary anatomy). 
4. Buccinator-group. 
PI. 8, fig. 1; PI. 16, fig. 12, 13, 14. 
From the anterior margin of the ramus ascendens of the 
lower jaw, from the adjoining mucous membrane of the cheek 
and from the upper jaw, there arises a massive bundle of longi¬ 
tudinal fibres with a long narrow tendon; on the upper jaw, 
the fascicles arise in a long row just above the gingiva. If we 
follow the superficial longitudinal fascicles onward (PI. 16, fig. 12), 
they gradually pass into a superficial layer of transverse fascicles 
which, indeed, in the posterior part, are interrupted by a longi¬ 
tudinal tendinous stripe from which the fascicles, running up¬ 
wards and downwards, arise. Thus, only the downwards directed 
fascicles form a direct continuation of the superficial longitudinal 
fascicles, whereas those running upwards appear like an inde¬ 
pendent layer. In the anterior half, on the contrary, the trans¬ 
verse fascicles run continuously from the upper to the lower jaw. 
Below this transverse layer the deep longitudinal fascicles 
proceed, in the form of a continuous layer, to the angle of the 
mouth (PI. 16, fig. 13). From the lower margin of the longitud¬ 
inal layer a portion is split off, m. depressor labii inf., and runs 
as an extended, flat, narrow, muscular body to »the chin«. 
Finally, there is, at about the middle third of the deepest 
part of the cheek — close to the mucous membrane — a layer 
of perpendicular fascicles (PI. 16, fig. 14). This layer also origin¬ 
ates from the longitudinal fascicles, a deep fascicle of the latter 
bending upwards, and being continued farther on by fascicles 
that gradually take the perpendicular direction. 
At the angle of the mouth the superficial transverse layer 
bends into the lips forming a very powerful and thick pars ri¬ 
mana. The pars supralabialis (the m. incisivus superior of the 
Veterinarians) is well developed, reaching with its origin almost 
on to i 2 , and having its fascicles arranged in the usual way. 
The m. nasalis is composed of three series of fascicles, aris¬ 
ing from the intermaxillary bone a little above the gingiva in 
the range from c to i 2 . Every series forms a flat, rather narrow 
layer; the two hindmost run obliquely upwards and backwards 
and it would seem that the fascicles end in the connective tissue 
inside the m. nasolabialis and maxillo-labialis; how far they — 
