BIRD. 



"lavicle ; and the Furcal bone, as being the most ante- 

 rior one, and the least connected with the sternum 

 was generally considered as the additional one, anc 

 the coracoid bones, which have nearly the same 

 relative position with regard to the sternum, as the 

 clavicles of mammalia, as the true clavicles of birds. 



But when we examine, with due attention, the 

 skeletons of all birds, whether capable or not capable 

 of flight, and if capable, whether they fly with more 

 or less power, we find that the coracoid is the true 

 distinguishing bone of the winged race the bone 

 which connects the anterior extremities with the 

 sternum as their grand support ; and that the furcal 

 bone is more or less perfect, or present, or wanting, 

 according to the difference of habit, as in the mam- 

 malia we must admit, with the illustrious author of 

 the Regne Animale,i\\&t that bone is really the clavicle; 

 and that the coracoid bone is just as essential to the 

 existence of a bird as the scapular bone is to that 

 of the mammalia. The humerus of the wing in birds 

 is as constantly articulated (that is, chiefly articulated) 

 upon the coracoid as the fure leg of the mammalia is 

 articulated upon the shoulder-bone, or blade-bone; 

 and the furcal bone is present in the one class when 

 the joints of the shoulders require to be kept asunder, 

 and absent when they do not, just as it is in the other. 

 Thus, in birds, we have the wing as uniformly 

 referred to the sternum, by means of the coracoid, as 

 we have the fore-leg referred to the muscles of the 

 shoulder and the spinous processes by which they are 

 supported in the mammalia ; and though both are 

 so placed that neither the one nor the other directly 

 disturbs the vertebral column, so as to derange its 

 important contents, yet they are very beautifully 

 arranged so as to suit the different systematic habits 

 of the animals. In the mammalia, an action of the 

 thorax in heaving and falling is required, in order to 

 carry on the process of breathing by means of lungs 

 and a moveable diaphragm exclusively; and there- 

 fore neither the weight of the anterior part of the 

 body, nor the motion of the fore-legs, could be, in 

 them, supported from the sternum, without confining 

 and disturbing that action. Thus the mammalia, 

 when they bear the weight on the fore-legs, have the 

 thorax free as it were, and suspended upon these fore- 

 legs as props, the muscles and other soft parts, which 

 attach the scapular bone to the body, affording an 

 elastic support, similar but superior to that of the 

 springs upon which the body of a carriage is hung. 



Birds, on the contrary, never have any support, 

 except by the feet, upon substances which are not in 

 themselves elastic, as the air or the water, and thus 

 the anterior part of their bodies is carried on the 

 sternum, as a basket or boat, that bone being always 

 more produced and developed in proportion as the 

 weight of the body is borne more upon it. If the 

 bearing is chiefly upon the wing, then the strength of 

 the sternum is concentrated forwards ; but if upon 

 the under surface of the body, as in the swimming 

 birds, then the sternum is produced backwards, or has 

 more of a boat shape. In birds that fly little, the 

 sternum is weak ; and in those which cannot fly it is 

 short, that it may be out of the way of the more 

 vigorous action of the legs which is required in them. 

 In both, and more especially in the latter, it serves 

 more as a breast-plate or buckler for supporting the 

 anterior part of the body, by reference to the spinal 

 column, and by moans of that to the logs, than as the 

 ultimate fulcrum of every sort of motion ; and in 



these birds the scapular bones, by means of which 

 the anterior part of the sternum is supported, or 

 rather by means of which it is suspended, are more 

 produced, and have their forms better adapted for a 

 tirm imbedment among the muscles of the back, 

 than in habitual flyers. So marked does this character 

 become, that in the ostrich tribe, which, as they do 

 not require the furcal bone to keep the heads of the 

 scapulars asunder have it only in two rudimental 

 processes, the coracoids and scapulars have much the 

 character and office of two hooks, which, taking hold 

 by means of their imbedment in the flesh, bear up 

 the anterior part of the sternum. 



This enlarged and basket or boat-shaped sternum, 

 together with the coracoid bones, are therefore to 

 be regarded as the most typical part not only of the 

 skeleton of birds, but of their whole organisation. 

 The form of the sternum varies much with the habits 

 of the different species ; but it is, in all cases, the 

 characteristic sternum of a bird, and in no species, 

 which has been examined, has it been found without 

 coracoids, though in those species where these do 

 little else than suspend the sternum they are united 

 into nearly one continued Hat piece with the scapulars. 



It is to be regretted that, hitherto, there has been 

 no opportunity of completing this part of the series 

 by examining the sternal apparatus of the apteryx, 

 which, as the most wingless of the class, and as being, 

 from the structure of its feet, a bird of slow motion, 

 must be the one which has the sternal apparatus most 

 exclusively formed for the support of the anterior 

 part of the body only. Thus in it we should have a 

 real analysis of this most characteristic part of the 

 structure of birds, not by mere dissection, where we 

 are left to guess at the use of the organ from its form 

 and its connexion with other organs, but actually in 

 the living bird. By this means we should be able to 

 separate the two functions of the sternal apparatus 

 tlie simple and more general, which supports the 

 body of the animal, and the more complicated and 

 variable, which relates to the operation of flying. 



Sterna of Wingless Bircbs. Wingless, though the 

 epithet commonly given to those birds that are 

 incapable of flight, is by no means an accurate one. 

 There is no bird absolutely wingless, even though 

 it should have the bones of the wing wholly within 

 the integuments. When we reflect a little on the 

 matter, we find that such might be expected. A 

 wing is an organ of flight, and the performing of 

 that operation is the chief apparent use of the 

 wing. But the wing is also, independently of its 

 action in flying, an integrant part of the structure of 

 a bird a part which the bird has, whether it be in 

 motion or at rest. Now, it should always be borne 

 in mind, that an animal is a perfect structure, and 

 that all its parts are in concert, whether it be in a 

 state of action or in a state of repose. One part does 

 not, therefore, merely press up, or move the other, 

 as in the case of our structures and machines. In our 

 moving structures we have to apply some external 

 power to put the structure in motion, after all its parts 

 are completed ; but the motive force of the animal 

 s internal, and we cannot locate it to one part of the 

 organisation. The animal has, therefore, the whole 

 of its structure consenting, and not merely consenting, 

 jut co-operating in all its actions and all its positions 

 of repose ; and it should seem that the shoulder-joint 

 of a bird is incapable even of supporting the sternum, 

 nd with that the under part 01 the body, so as to 



