The number of the dorso-lumbar
vertebrae in this group is always fewer than twenty-two, and
rarely exceeds nineteen.
The third digit of each foot is asymmetrical in itself, and
usually forms a symmetrical pair with the fourth digit; and
the functional toes of the hind-foot are even in number-that
is to say, either two or four.
The femur is devoid of any third trochanter; the facets
upon the distal face of the astragalus are subequal, that for
the cuboid being nearly as large as that for the navicular
bone. The tympanic is large, and the pterygoid process of
the sphenoid is not perforated.
The posterior premolar teeth usually differ a good deal
from the succeeding molars, being simpler in pattern. The
last milk-molar in the lower jaw is trilobed; but this is also
the case in some Perissodactyla.
The stomach is more or less complex. The caecum, though
well developed, is smaller than in the Perissodactyla
The mammae are inguinal or abdominal. When horns are
present, they are double, supported, wholly or partly, by the
frontal bone and provided with an osseous core, which is
almost always an outgrowth from that bone.
are divisible into the Non-Ruminantia
and the Ruminantia.
A. The Non-Ruminantia
usually have more than one pair
of incisors in the upper jaw. The molar teeth have either a
mammillate, a transversely-ridged, or a rhinocerotic pattern.
In only one genus, Dicotyles
, are any of the metacarpal or
metatarsal bones anchylosed together. They are devoid of
horns, and the stomach has rarely more than two divisions.
are divisible into three families:
, the Hippopotamidae
, and the Anoplotheridae
more or fewer of the members of this last group may have ruminated.
have the skin of moderate thickness and
hairy; the limbs slender, and the third and fourth toes considerably
longer than the second and fifth. The teats are
abdominal, and there is a scrotum. The dental formula varies
considerably, but the molars have a multituberculate or transversely-ridged grinding surface.
In the genus Sus
, the dental formula is i.
By way of contrast with the Horse, I add some more detailed
statements regarding the anatomy of the Pig as a common
and very good example of an Artiodactyla. The Pig has
seven cervical vertebrae, nineteen (Exceptionally, the number may be increased to twenty-two.)
dorso-lumbar, of which
fourteen are dorsal, four sacral, and twenty to twenty-three
caudal. The atlas has wide oblique alae, as in the Horse.
The centra of the other cervical vertebrae are short, with
nearly flat articular surfaces, and this flatness is retained in
the dorso-lumbar region. The cervical and dorsal vertebrae are
provided with long spines, that of the first dorsal vertebra
being the longest of all. Up to the twelfth dorsal the spines
all slope backward; beyond it they slope forward, if at all.
In the ninth dorsal vertebra the postzygapophysis presents
an articular surface on its dorsal side, and the prezygapophysis
of the tenth vertebra bends round so as to overlap this surface.
This character is continued in the succeeding vertebrae as far
as the first sacral. The transverse processes of the penultimate
and last lumbar vertebra are tolerably long, but they are
inclined forward as well as outward, and do not articulate
with one another, or with the first sacral.
In the skull the supraoccipital is inclined upward and forward
into a great transverse crest, to which the parietals contribute
but little. The parietals are early anchylosed. The
temporal ridges remain widely separated in the middle of the
roof of the skull.
The frontal bone has a post-orbital process, and so has the
jugal, but the two do not meet so as to bound the orbit. The
lachrymal is very large, and its two canals open on the face.
The nasals are very long, and the premaxillae unite with them
for a great distance. There is a praenasal bone, or ossification
of the cartilaginous septum of the nose. The bony palate extends
back beyond the level of the last molar. The base of
the external pterygoid process is not perforated. The surface
for the articulation of the lower jaw is transversely elongated,
convex from before backward, and bounded behind and internally
by a post-glenoidal ridge.
The tympanic bulla is very large, and the exceedingly long
bony meatus curves upward and outward, between the squamosal
and the mastoid, with both of which it is anchylosed, to
the root of the zygoma, where its aperture looks almost directly
upward. The post-tympanic is closely appressed to the postglenoidal
process, so as, with the latter, to encircle the meatus.
The proper mastoid is distinct, though short, but there is a
very long paramastoid developed from the exoccipital and extending
behind and below the mastoid.
The rami of the mandible are completely anchylosed at the
symphysis. There is a long perpendicular portion of the
ramus. The condyle is transversely elongated and. convex,
antero-posteriorly; the coronoid process ascends hardly higher
than it. In a longitudinal section, the cavity of the cerebral
hemispheres is more rounded than in the Horse, and lies
above, as well as in front of, that for the cerebellum.
The scapula is long and narrow. It is devoid of acromion,
and has but a small coracoid process.
The radius and ulna are complete, but are anchylosed together
in the prone position. The distal end of the ulna
articulates with the cuneiform bone.
The carpus contains eight bones, but the radial bone in
the distal series may be either the trapezium, or a rudiment
of the pollex. The lunare and the axis of the third metacarpal
have the same relation as in the Horse. The third and fourth
digits are larger than the other two, and form a symmetrical
pair. There are sesamoid bones on the ventral face of the
articulations between the metacarpal and the basal phalanx,
and of that between the middle and the distal phalanges.
Each distal phalanx is incased in a small hoof. The femur
has a round ligament. There is no third trochanter. The
fibula is complete, and its distal end articulates with the calcaneum.
There are the usual seven tarsal bones. The tibial
end of the astragalus has the form of a deeply-grooved pulley,
the direction of the groove corresponding nearly with the
length of the foot. The distal end presents a convex subcylindrical
surface divided by a ridge into two facets, of
which one is somewhat less than the other, and articulates
with the cuboid.
The metatarsus and phalanges of the pes are disposed like
the corresponding bones in the miinus.
The fore-part of the body is supported upon the anterior
extremities by a muscular sling composed of the serratus, levator
, and sternoscapularis
, much as in the Horse,
with which the Pig exhibits a general correspondence in its
myology. The muscles which move the digits, however, have
undergone less modification. Each digit of the manus, for
example, has its proper extensors, and there is an extensor ossis
which ends on the basal phalanx of the
second digit. A pronator teres
is inserted into the lower half
of the radius. The flexor perforatus
has only two tendons,
which go to the third and fourth digits. The flexor perforans
sends two large tendons to the third and fourth, and two small
ones to the second and fifth digits. There is a large interosseus
muscle on the radial side of the third digit, and another
on the ulnar side of the fourth; but the interossei
of the interspace
between these digits are represented only by fibrous
tissue. The second and fifth digits have each two interossei
There is no soleus
. The strong and fleshy plantaris
from the outer condyle, beneath the gastrocnemius;
between the two heads of the latter, passes to the
inner side of the tendo Achillis
; its tendon curves round this
tendon, passes over the end of the calcaneum as over a pulley,
enters the sole, and finally divides into the two perforated
tendons of the third and fourth digits. The inner and outer
digits, of the pes, like those of the manus, have no perforated
A large and fleshy flexor hallucis longus
arises from the
fibula and the interosseous ligament, and its broad tendon
passes into the sole and coalesces with the tendon of the
smaller flexor longus digitorum
. The conjoined tendons divide
into four slips-two large, median, and two small, inner and
outer. These go to the distal phalanges and sesamoids of the
The tibialis posticus is absent, but there is a small tibialis
A very complicated muscle represents the extensor longus
and the peronaeus tertius.
It arises by (a) a strong
round tendon from the outer condyle of the femur, just in front
of the external lateral ligament. From this tendon proceed
two fleshy bellies, one of which supplies tendons to the third,
fourth, and fifth digits, while the other ends in a broad band
of tendinous fibres, which is inserted into the third metatarsal
and the ectocuneiform. Into this band is inserted (b)
second fleshy head which arises from the upper part of the
tibia; and it is traversed by the tendon of (c)
the third head,
which is slender, arises from the fibula, and sends its long and
delicate tendon to the dorsum of the second digit.
The peronaeus longus
is present, and its tendon is inserted
into the entocuneiform and the second metatarsal. There is
no peronaeus brevis.
A peronaeus 4ti et 5ti digiti
the upper part of the fibula, behind the peronoeus longus,
ends in a tendon which passes behind, and on the inner side
of, that of the latter muscle, to the dorsum of the foot, where
it divides into two branches which join the extensor sheaths
of the fourth and fifth digits.
The extensor brevis
goes to the two middle digits, and is
connected with the middle tendon of the extensor longus.
are similar to those of the manus
The formula of the milk dentition of the Pig (which is complete
at the third month after birth) is d.i.
The outer upper incisors are directed obliquely outward
and backward. In the upper jaw, the anterior two molars
present sharp longitudinal edges, while the posterior two
have broad crowns with two transverse ridges. In the mandible
the anterior three molars have sharp longitudinal edges,
while the hindermost has a broad, three-ridged crown.
The first permanent molar is the first tooth of the permanent
set which comes into place (at about six months after
birth), and the permanent dentition is completed in the third
year, at which time the first deciduous molar, which is not
replaced, falls out. Hence the formula of the permanent
dentition is i.
The permanent incisors in the upper jaw have short, broad,
vertically-disposed crowns, and lie in a longitudinal series, the
external being separated by an interval from the others. The
elongated inferior incisors lie side by side, are greatly inclined
forward and upward, and are grooved upon their upper or
inner faces. The strong, angulated crowns of the canines are
bent upward and outward in both jaws. They work against
one another, in such a manner that the upper wears on its
anterior and external face, the lower on the posterior aspect
of its apex. The crowns of the premolars are all brought to a
cutting longitudinal edge, while the molars have broad crowns
with transverse ridges subdivided into tubercles. Of these
ridges there are two in the anterior two molars of each jaw,
while the posterior molar is more complex, having at fewest
three distinct ridges. The molar teeth all develop roots; but
the canines continue to grow for so long a time, in the Boar,
that they might be said to be rootless.
The alimentary canal is ten or twelve times as long as the
The stomach is less simple in structure than it appears to
be at first sight. The cardiac end presents a small caecum, in
which is a spiral fold of the mucous membrane; and, at the
entrance of the oesophagus, the epithelial lining is folded so
as to form a sort of valve. Folds of the mucous membrane,
between which there lies a groove, extend from the cardia
toward the pylorus, and foreshadow the more developed structure
observable in Ruminants.
The caecum has not above one-sixth the capacity of the
stomach, and the ilium projects into it, so as to form a very
efficient illocaecal valve. The liver is provided with a gallbladder.
The heart is devoid of a Eustachian valve, and
sometimes, but not always, possesses a septal ossification.
There is only one anterior cava. The aorta gives off an innominata
whence the right subclavian and the two carotids
arise, and a left subclavian. This is an arrangement midway
between that observed in the Horse and that in Man.
The trachea, before it divides, gives off a third bronchus,
which passes to the right lung; and the lungs are deeply lobed.
In the brain the cerebral hemispheres rise above the cerebellum
much more than they do in the Horse.
In the male, the penis is contained in a long prepuce, and,
like that of the Horse, is devoid of a bone and provided with
retractor muscles. The prostate is lobed. There is a large
uterus masculinus and well-developed vesiculae seminales.
The ducts of Cowper's glands open into a caecal cavity contained
in the muscular bulb. The testes descend into a scrotum.
In the Sow, a pair of Gaertner's canals,
Wolffian ducts, open into the vestibule beside the urinary
meatus. The uterine cornua are very long, and the ovaries
are lobulated. The period of gestation is sixteen to twenty
weeks. The ovum, at first spherical, retains that form until it
attains a diameter of nearly half an inch. It then rapidly
elongates into a coiled filiform body, as much as twenty inches
long. Both the allantois and the umbilical vesicle at the same
time assume a spindle-shape.
The allantois soon becomes divided into an internal epithelial
and an external vascular layer; the latter becoming united
with the chorion, through the extremities of which the allantois
eventually passes. The villi are very numerous, minute,
and spread over the whole surface of the ovum.
exhibit great variations in their dentition and
in the structure of the stomach.
(the Babyrussa) the dental formula is i.
5.5/5.5; the canines are enormously elongated and recurved,
and the pharynx is provided with peculiar air-sacs.
The stomach is divided into three chambers, and the groove
leading from the oesophagus toward the pylorus is more distinctly
marked than in the Sus
(the Peccaries) the upper incisors are also
reduced to two on each side, and the molar teeth present
transverse ridges, which are more distinct and less tuberculated
than in Sus
The stomach is divided into three sacs, and is provided
with an oesophageal groove as in the preceding genus.
The middle metatarsals and metacarpals coalesce into a
cannon-bone, and the fifth digit of the pes is represented only
by its metatarsal.
(the Wart-hog) the upper incisors are
reduced to one pair, and the hindermost molars, which are the
only ones which are not shed in the old animal, are of great
size, and possess a complicated, tuberculated structure.
are represented by one genus or another in all
the great distributional provinces except the Australian
(The Papuan pig may have been introduced from the weatward.) and
is peculiar to part of the Malay Archipelago, Dicotyles
to South America, and Phacochaerus
to South Africa.
A great variety of swine-like Ungulata
existed during the
deposition of the older tertiary strata, and are the earliest
known members of the group.
are represented at present only by
the genera Hippopotamus
have a huge head, a heavy body, covered with a thick integument,
provided with scanty hairs, and short, stout, tetradactyle
limbs, all the four toes of which rest on the ground. The
female has inguinal teats, and the male is devoid of a scrotum.
The dental formula of the adult Hippopotamus
3.3/3.3, while Chaeropus
has only two incisors in
the lower jaw. The tubercles of the molar teeth, when ground
down by mastication, present a double trefoil pattern, and the
hindermost inferior molar is trilobed. The incisors are straight
and tusk-like. The very large and curved canines are directed
downward in the upper jaw, upward in the lower. Their mutual
attrition wears the anterior face of the extremity of the
upper, and the posterior face of that of the lower, flat.
The milk dentition consist of d.i.
1.1/1.1 d.m. 4.4/4.4
The last lower deciduous molar is trilobed, and the first deciduous
molar persists a long time, and seems not to be replaced.
The stomach is divided into three or four compartments,
and there is no caecum. The liver has a gall-bladder, and the
kidneys are lobulated.
The skeleton is very pig-like, but in some respects approaches
the Ruminants. The centra are slightly convex in
front, and concave behind, in the cervical region, but not elsewhere.
The prezygapophyses overlap the postzygapophyses
in the posterior dorso-Iumbar vetebrae. On the other hand, the
transverse processes of the last lumbar vertebrae articulate
with those of the preceding and succeeding vertebrae, as in
the Horse and other Perissodactyles.
In the skull the orbits are nearly complete posteriorly, and
they become almost tubular by the outward production of the
frontal and lachrymal bones.
The nasals and premaxillae unite for a great extent. The
osseous palate is long; the large tympanic bone is anchylosed
with the approximated post-gienoidal and post-tympanic processes.
The mandible is extremely massive, and has a backwardly
The scapula has a short acromion. The radius and ulna
are complete and anchylosed, and there are eight bones in the
carpus. The fibula is complete, and the tarsus, which has
seven bones, much resembles that of the Pig.
are at present confined to Africa;
but a species abounded in the rivers of Europe in the later
of the miocene Fauna of the Sewalik
Hills appears to have been a Hippopotamid, with upper molars
having a quadri-crescentic, ruminant-like pattern, and lower
molars bi-crescentic and rhinocerotic in character.
In the Suidae
, it is interesting to
remark the tendency to the coalescence of the metacarpals
and metatarsals in Dicotyles
; the disappearance of the upper
incisors by pairs in Dicotyles, Parcus,
the great complexity of the stomach in Dicotyles
as they are so many approximations toward the
structure of the Ruminant Artiodactyla
. And the transition
from the non-Ruminant to the Ruminant groups, or rather the
common stem of both, is furnished by the Anoplotheridae
The family of the Anoplotheridae
extinct Mammals belonging to the eocene and miocene epochs.
They are most conspieuously distinguished by the circumstance
that the teeth, of which there are eleven on each side, above
and below, in the adult dentition, are not interrupted by any
gap in front of and behind the canine, as they are in the preceding
genera, but form an uninterrupted and even series, as
The dental formula of the adult Anoplotherium
3.3/3.3, supposing that the first premolar is really
such, and not a persistent milk-molar.
|Fig. 101. The skeleton of an Ox (Bos)
The upper and lower molars have the general structure of
those of the Rhinoceros; but the laminae of the upper are Lent
more backward into parallelism with the outer wall, and a
strong conical pillar is developed on the inner side of the
anterior lamina. The skull resembles that of the Ruminant Tragulidae
in structure, but the orbit is incomplete behind
The rest of the skeleton partly resembles that of the Pigs,
and partly that of the Ruminants.(It Anoplotherium secundauium
is developed in each foot,
though not nearly so long as iii.,
which is nearly symmetrical in itself. Then
is an approach to the same structure in the manus of Cainotherium.
, which are ordinarily comprised
among the Anoplotheridae
(though, in all probability,
they are true Ruminants of the Traguline group), the orbit is
complete, and both upper and lower molars put on the Ruminant
characteristics. In dentition, Cainotherium
a Ruminant only in possessing all the upper incisors, while
no existing adult Ruminant has more than the outer upper
incisors. We are of course unacquainted with the structure
of the stomach in these animals, but they so closely resemble
that it is highly probable they may
have possessed the faculty of rumination in a more or less perfect