OSSEOUS SYSTEM. (Comp. Anwar.) 
portion of the skeleton into an osseous frame- 
work able to sustain the stress of. those power- 
ful muscles that wield the instruments of 
flight. At one end each of these pieces 
is moveably articulated with the distal ex- 
tremity of the corresponding dorsal rib, whilst 
at the opposite it is firmly attached to the sides 
of the expanded sternum by joints that admit 
of a certain extent of motion. 
It is in the Chelonian Reptiles that these 
accessory portions of the thorax attain their 
greatest growth, spreading into broad plates 
that are connected by strong sutures to the ex- 
tremities of all the spinal ribs and likewise to 
each other in the Tortoises, completing thus 
the cara or dorsal shield; and, moreover, 
__ being solidly united at the sides with the enor- 
_ mous apparatus of sternal bones, the whole 
__ body of the Tortoise becomes encased in bony 
_ armour, derived entirely from the thoracic 
_ elements of the skeleton. 
: The anTerror timss of Vertebrate animals, 
_ although essentially composed of similar ele- 
ments throughout all the classes belonging to 
this great division of animated nature, are 
made subservient to very various and opposite 
uses; the pectoral fin of the Flying Fish, the 
enormous hand of the Skate, the paddle of 
the Turtle, the flipper of the Whale, the wings 
of the Bird and of the Bat, the broad shovels 
of the Mole, and that masterpiece of organiza- 
_ tion, the human hand, being respectively but 
_ simple modifications of the same structure. 
In the osseous Fishes, indeed, it is not 
always easy to recognise the elements that are 
correlative with those of the higher Vertebrata ; 
but a little attention is sufficient to prove the 
construction of the pectoral fins among the 
_ finny tribes to be true representatives of the 
_ anterior extremities of other races, as will be 
_ evident from the following masterly analysis of 
the parts composing the pectoral fin of the 
_ Perch, given in Cuvier’s great work on Fishes. 
_ Immediately behind the gill-openings there is 
placed on each side a framework of bones 
that bound the branchial apertures. This frame 
| is attached superiorly to the back of the head, 
butinferiorly the two halves are united together, 
‘forming a bony zone that surrounds the body 
this part; and being connected inferiorly 
vith the body of the os hyoides, forms here a 
kind of isthmus that separates the gill-open- 
“ings from each other. The bony zone above 
“described is made up on each side of three 
| pieces, which represent the bones of the 
Shoulder and of the arm, to which is affixed 
steriorly a group of two or three other bones 
“that represent the forearm, wherewith is con- 
“nected the fin itself, the representative of the 
hand. The names applicable to these pieces 
Of the skeleton when their analogies are strictly 
Investigated are as follow :—The suprascapular,* 
the scapular,t the humerus,} the radius and ulna, 
‘ 
po 
ad 
2. Synonyms — Omoplate, Omolite, Pedicule de 
5 t Syn,— Omoplate (Geoffroy), Acromion ( Bakker). 
_ + Syn.—Clavicle (Meckel, Geotl.), Camosteon 
(Bakker). 
eae 
839 
to which succeed the carpal bones and the 
phalanges of the fin, In addition to these must 
be noticed the two pieces regarded by Cuvier 
as representing the coracoid bone of Reptiles. 
When fully developed, the anterior extremity 
is made up of a greater number of elements 
than exist in the human skeleton. The shoulder 
is a strong framework, composed of three dis- ~ 
tinct pieces, named respectively the scapula, 
the clavicle, and the coracoid bone. The other 
bones of the limb resemble each other in their 
general arrangement throughout all the Verte- 
brata, and in the Crocodile, where all parts of 
the limb present a mediym state of develope- 
ment, the analogies between the bones com- 
posing it and those of the human arm are at 
once recognised. The humerus, a single bone, 
supports the first division of the limb. Two 
bones, the radius and the ulna, are met with 
in the forearm, while the bones of the carpus, 
the metacarpus, and the phalanges of the fingers 
present an arrangement similar to what is found 
in the human body. In order, however, to 
appreciate the important modifications required 
in the disposition and conformation of these 
elements in the different races possessing them, 
it will be needful to examine them successively 
in the order in which they have been enu- 
merated. 
The scapula is the most important piece 
entering into the composition of the shoulder, 
and not unfrequently, among the Mammiferous 
races, is the only bone developed for the sup- 
port of the anterior limb. In Reptiles and in 
Birds, where so great freedomt of motion as is 
required in terrestrial Quadrupeds would be 
inadmissible, the movements of this part of 
the skeleton are considerably restricted, and a 
kind of anterior pelvis formed which gives 
great strength and firmness to this part of the 
skeleton. The scapule are generally laid like 
splints along the exterior of the chest, in which 
position they are, as it were, suspended by 
strong muscles; but frequently this arrange- 
ment is necessarily departed from for obvious 
reasons. In the Batrachia, for example, such 
as the Frog and the oad, the ribs are 
altogether wanting, and the strength of the 
shoulder must consequently be provided for in 
a peculiar manner. The scapule are enormously 
developed so as to perform, to a certain extent, 
the office of ribs; and, moreover, each being 
divided, as in Fishes, into two portions, united 
by cartilage to each other, the strength and 
resiliency of a chest is in some measure obtained. 
It is, however, in the Chelonian Reptiles that 
the most extraordinary deviation from the usual 
arrangement is witnessed, where the scapule 
are absolutely placed in the interior of the 
thorax, where they are connected by one extre- 
tremity to the sides of the bodies of the dorsal 
vertebra. 
No spine or acromial process exists in the 
scapule of the oviparous Vertebrata, and even 
in the quadrupedal Mammals these parts of the 
bone are very imperfectly developed when com- 
pared with their condition in Man, in whom 
alone they assume their full importance. 
The clavicle forms the second element em- 
