THE MAMMALIA— MAN AND BEASTS. 
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food to tHc mouth by means of hands, or of feet constructed somewhat similar to 
hands. Neither do we find it in the Elephant, where the proboscis is substituted for 
hands, nor is it to be found in the Cetacea, which obtain their food in water: the 
latter possess the shortest necks of all the ^Mammalia. It appears singular that the 
number of cervical vertebraj should remain constantly the same, although the necks 
of different animals differ so very widely in length. In Msm, we sometimes observe 
the vertebrae of the back and loins to vary from their usual number, but never those 
of the neck. 
The Dorsal Vertebrae are very large and long in all quadrupeds with long necks 
and ponderous heads, especially in the Horse, Camel, Elephant, and Camelopard, 
which arrangement seems necessary to afford a place of attachment for the Ugamentum 
nucha. 
The number of Lumbar Vertebric varies exceedingly in different Mammalia; and 
when the length of the body is remarkably great, it is usually occasioned by a greater 
or less number of those vertebr® of the loins. Their motion is more or less restrained 
in nearly all quatlrupcds; and this is effected by the exterior side of each posterior 
articular process being directed backwards, so that the anterior articular process of the 
next vertebra falls between two prominences. The shape of the body in animals, 
whether slender, short, or thick, is chiefly determined by the length of the loins, and 
this again depends upon the number of the lumbar vertebrne. 
The anterior ribs are attached in front by cartilaginous portions to a 
sternum or breast-bone, composed of a certain number of vertical pieces. 
Some of the ribs are attached only by the hinder extremity to the spine, and are 
called yh/jc or shaking rihSj to distinguish them from the true, which are united to 
the sternum. The ribs of the Mammalia vary greatly in number. In no instance is 
the total number less than twelve, being the number in the human skeleton. The 
horse has 18 ribs, being 8 true and 10 false; the Elephant has 20 ribs, being 7 true 
and 13 false. The strength of the spinal column, and its consequent ability to sustain 
great weights, depend very much upon the size of the ribs, and upon the figure which 
they give to the rest of the body; accorilingly, we find that in the large herbivorous 
quadrupeds, which are usually employed as beasts of burthen, the ribs arc thick and 
broad. Those quadrupeds which have no clavicles have less curvature upon their 
sides than the others. Being never required to use the anterior extremity as a pre- 
hensile member, the chest h narrowed and flattened upon the sides, especially towards 
the sternum, whereas Mammalia with clavicles have their chest shaped nearer to the 
human form. 
The ribs are remarkably strong and compactly set in all quadrupeds destined to 
roll themselves up when attacked by other animals. In all Mammalia, they have only 
a very limited motion upwards and downwards, and their articulations are strengthened 
by a great number of ligaments. There are capsules at each articulated extremity of 
the ribs, which retain them upon the bodies .Tud transverse processes of the vertebraj. 
They are further secured by means of two ligaments, the one being inserted into tho 
transverse process of the superior vertebra on the inside, and tho other into tho low'er 
articulating projeetiem of the same vertebra, but on the outside. By this means the 
cavity of tho chest is rendered secure, as well as by tlie capsule which unites the 
ether extremity to the prolonged cartilage of the breast. There is also a ligamentous 
expansion between the ribs, connecting the lower edge of the one rib to the upper 
edge of the next. 
In all animals, excepting perhaps the I^Iai’mot, tho thorax or chest is narrower than 
In Man, and deeper from the spine to the breast. I’his peculiarity arises from the 
greater length of their breast-bone, and the less-marked flexure of their ribs. The 
flamelopard, and other animals having very long legs, possess the kecl-likc form of 
the chest in a rem:u'kable degree ; this is especially observable in the Door tribe. 
Tho Sternum, or Breast- bone, differs generally from that of man, in being composed 
of a greater nmubor of pieces, and in being rounder and narrower. It is also longer 
in proportion to the rest of tlio body. In tbe Mole, the sternum Is remarkably thick 
and strong. To enable this animal to excavate the eartli for the admission of its 
^ody, the anterior portion of the clavicle is comj»rcssed upon the sides, so as to give it 
fho form of a ploughshare. It projects heyoiui tho line of the first rib, and thus 
enables the animal to burrow with singular rapidity. 
The anterior extremity of the Mammalia commences in a shoulder-blade, 
"hich is not articulated, hut merely suspended m the flesh; often resting 
On the sternum, by nu!ans of mi intermediate bone, called a clavicle. 
The anterior extremities, or f<n*c-Hmbs, often appear to differ widely from each other 
^pon superficially comparing the external forms in different species with each other 
•■wid with ISian; thus, the Dolphin and Whale seem to possess fins, and the Bat wings, 
this difference is more apparent than real. Upon examining their internal struc- 
ture, we find that tho forc-Umb consists always of four component jiaris, the Scapula 
shoulder, the Humerus or arm, the Pore- Arm, and the Hand. In the fins of the 
Uetacca we perceive all those bones'flattened in their form, and scarcely capable of 
*rtoving upon each other, while the wing of the Bat is really a hand, with its fingers 
excessively clongatetl. There arc also found a ehias of limbs intermediate between 
Ike fore-foot of the quadruped and the pectoral lins of the Cetacea. TIjo Otter, Seal, 
^tid Walrus, have their bones covered witli a web-liko integument, adapti-d for tho 
purpose of swimming. Tlieir limbs ar**. much more freely developed than in tho Ce- 
ta-coa, and possess a greater freedom of motion, so that they form an intermediate 
transition from the one structure tu tho other. 
The Scapula, or shoulder-blade^ is found in all Mammalia. In general, the edge 
this bone, next to the spine, is rounded, and the posterior angle is thus rendered 
klunt. The shape of the Scapula depends on the presence or absenco of a clavicle; 
the acromion not being so pronunent when this clavicle is absent; and then there is 
^•nothcr process called the recurrent proceitx.^ ])ointing backw'ards almost perpendicularly 
to the spine. The posterior angle is also most elongated in those .species having com- 
plicated motions of the anterior limbs. In animals having only the rudiments of 
<ilavicles, or none, tho acromion process is nearly deficient. 
The Clavicle, or Collar-bone, is not found m species which employ their anterior 
9 
limbs only for progressive motion. In the Mole, the clavicle is of an extraordinary thick- 
ness, being nearly square, and slightly greater in breadth than in length. In the Bat, 
it is very large and strong. Indeed the Clavicle is found in all Mammalia which use 
llieir forc-lirabs for burrowing, like the Mole; for raking the ground, like the-IIedge- 
hog and Ant-eater; for climbing, like the Sloth; or for holding objects, like the 
Beaver and Squirrel. In tho other Maramulia, we often find in its place a smaller 
bone called the Os claviculare, analogous to tho true clavicle, but merely connected 
to the muscles. This arrangement is observed in most Cavnassiers, and in many 
Rodentia. 
Sir Cliarles Bell observes, that “ Animals which fly, or dig, or climb, as bats, moles, 
porcupines, squirrels, ant-eaters, armadilloes, and slotlw, have the clavicle ; for in them 
a lateral or outward motion is required. There is also a certain degree of freedom in 
the anterior extremity of the cat, dog, marten, and bear; they strike with the paw, 
and rotate the wrist more or loss extensively ; and they have thcreforo a clavicle, 
though an imperfect one. In some of these, even in the Lion, the bone which has the 
place of the clavicle is very imperfect indeed; and if attached to the shoulder, it does 
not extend to the sternum, it is concealed in the flesh, and is like tho mere rudiments 
of the bone. But however imperfect, it marks a correspondence in the bones of the 
shoulder to those of tho arm and paw, and the extent of motion enjoyed. When the 
Bear stands up, we perceive by his migainly attitude and the motion of his paws, that 
there must be a wide difference in the bones of his upper extremity from those of the 
Ruminant or Solipede. He can take tho keeper’s hat from liis head and hold it; ho 
can hug an animal to death. Tho Ant-bear especially, as he is deficient in teeth, 
possesses extraordinary pow'ers of hugging with his great paws: and, although harm- 
less in disposition, he can squeeze Ins enemy, the Jaguar, to death. These actions, and 
the power of climbing, result from the structure of the shoulder, or from possessing a 
collar-bone, however imperfect. Although the clavicle is perfect Jn man, thereby 
corresiionding with tho extent and freedom of tho motion of his hand, it is strongest 
and longest, comparatively, in tlie animals which dig or fly, as in the I\Iole and the Bat.” 
It follows from these observations, that animals possessing a clavicle, and thus having 
the power of liugging, arc unable to bear a severe shock on their fore-limbs without 
running the risk of fractuiung the collar-bone. ** If -vve observe the hones of the 
anterior extremity of the horse,” continues the same eminent anatomist, we shall 
see that tho scapula is oblique to tho chest ; the humerus oblique to the scapula; and 
the bones of the furo-arm at an angle with the humerus. M''ero these bones connected 
together in a straight line, end to end, the shock of alighting would be conveyed through 
a solid column, and the bones of the foot, or tho joints, would suffer from the con- 
cussion. Wliqn the rider is thrown forwards on his liands, and more cenamly when 
ho is pitched on his shoulder, the collar-bone is broken, because in man this bone 
forms a link of connection between tbc shoulder and the trunk, so «'is to receive the 
whole shock ; and the same would happen in the horse, the stag, and all quadrupeds 
of great strength and swiftness, were not tho scapulic sustained by muscles, and not by 
bone, and did not the bones recoil and fold up.” 
Tho varieties of form observed in tUo clavicles are very great. In the Two-toed 
Sloth they have tho form of a rib ; in the JMole they are nearly cubical. The cla- 
vicles arc very long in the Bat, but in the Quadrumana they greatly resemble the 
same bone in Man. The clavicle is not found in the Cetacea, Ruminantia, or Soli- 
peda, and generally it is deficient in all long-legged quadrupeds, having a keel-shaped 
chest. 
The anterior extremity of the Mammalia is continued by an arm, a 
fore-arm, and a hand. 
The Arm-bone, or Iluraenis, varies considerably in the elevation of its processes, and 
in its length and breadth. In quadrupeds, the Humerus is much shorter compara- 
tively than in the human subject. It was this circumstance which has led tho ancient 
anatomists, and persons ignorant of Comparative Anatomy, to consider quadrupeds as 
liavitig tho elbow turned forw’ards. That part which is usually considered the knee 
of a Horse, corresponds to tho human wrist, the arm-bone being concealed witliin the 
muscles of the shoulder. The Humerus is very long in the Bat, but very short and 
thick in tho Mole. 
The human fore-arm is composed of tw’O distinct bones, the Ulna and the Radius ; 
fnc former swings with a hinge-like motion upon the elbow, and the latter gives the 
wrist and hand a rotatory motion. Accordingly, in all animals which use their fore- 
arms, like ISIan, for other purposes than walking, both of these bones arc distinctly 
developed; but. hi the true quadrupeds the Ulna diminishes in size, is altogether 
.absent, or becomes a mere appendage to tho Radius, which is then tho principal bone 
of the fore-ann. In cattle, tho Ulna is imraoveably united to the Radius throughout its 
entire length, becomes finally ossified, and may then be considered but as a single bone. 
They thus form a perfect hinge-like joint, which does not admit of any rotatory motion, 
and having the pulley placed on the end of the Humerus. These quadrupeds have 
therefore their anterior extremities always in a state of pronation, that is, the back of 
the wrist is always turned upwards. 
The general arrangement of the bones in the anterior limbs, though the same 
throughout tlie entire chiss, yet changes surprisingly in its details with the different 
orders and genera. In tho Bat the radius is nearly deficient, being reduced merely 
to a slLMider and sharp-pointed rudiment. Its thumb is short, and fiirnislied with 
a hooked nail, while the phalanges of the four fingers have no nails, but are extremely 
long and thin, almost like the spines of a fish, ivliile the membraneous, or wing-like 
expansion, is extended upon them. Again, in tho Mole, we see a striking diflerence 
in the form of the anterior extremity. The bone of its fore-arm is thin in the middle, 
but surprisingly cx])anded at cither extremity; and a peculiar bone, called tho falci- 
form bone, is found at the extremity of the radius. Its paw is shaped like a shovel, 
tho phalanges of the fingers. are supplied with scsa7noid bones and numerous processes, 
witich increase the angle of itiscrtion for the tendons, and fticilitate the great muscu- 
lar motion required by this little animal. The Flying Squirrel possesses a peculiar 
arrangement for enabling it to spring from groat heights. This consists in a sharp- 
pointed bone at the outer edge of its ^^rist, connected to that part by means of two 
smaller round bones. 
