576 
Mr. De la Beche and Mr. Conybeare on 
Concerning the ribs, we have no new remark to offer, with the 
exception that a careful examination of many specimens has 
convinced us that they did not form a single continuous arc, as the 
appearance of a single specimen induced Sir Everard Home to 
believe, but consisted of separate ribs on either side with intercostal 
bones lying between them and attached to them by cartilages. 
Bones of the Sternum and anterior extremities .* 
These have been most correctly and beautifully represented in 
Phil. Trans, for 1817 and 1820, but it is with great diffidence 
that we venture to differ from Sir Everard Home in the analogies 
and names ascribed to the several parts. 
In the first place, we may observe an arched bone having a flat 
process proceeding from the bottom of the arch. The whole form 
and apparent position in the skeleton is very analogous to that of 
the bone commonly called the merry-thought, and technically, the 
furcula, in birds, f but its inferior process is parallel instead of being 
* In the text the appellation of clavicles has been assigned to those bones in the skele- 
tons of the Orders, Reptiles and Birds, which are so denominated by M. Cuvier, in his 
memoir on fossil crocodiles, by Blumenbach, and the more common treatises on com- 
parative anatomy. It has been suggested to me however that more recent observations 
seem to demonstrate the analogy of these bones with the coracoid processes of mammalia 
rather than with clavicles, and the furcula forms in fact the true representative of the 
latter. If this view be admitted, as it has successively been by M. Cuvier, it will be 
proper to substitute in the text the term coracoid bones for clavicles, and clavicular arch 
for furcula. The arguments on which the above changes are founded proceed from the 
consideration of the muscles originating in the bones in question. 
+ It may seem extraordinary to search for an analogy in the structure of animals of so 
widely different an order as birds, when treating of any part of the skeleton of a species 
intermediate between crocodiles and fishes; yet the general disposition of the arched 
bone, the scapulas, and clavicles, is so very similar that it is impossible not to remark the 
resemblance ; and when it is considered that the employment and motion of the paddle 
in swimming has many points of agreement with that of the wing in flight, “ remigio 
alarum,” we cannot be surprised that nature, ever ceconomical in the application of her 
means, has given a similar structure to the parts adjacent to the anterior extremities in 
both instances. 
