166 OSSEOUS, MUSCULAR, AND NERVOUS SYSTEMS 
cess bears a close resemblance to the clavicle in birds ; 
whilst the bones I have called Clavicle (three in number) 
are very analogous to ^the fork or merry-thought found in 
the same class of animals. With regard to the flat, moving, 
squamous bones situated behind the clavicle, and fixed to 
the sternal portion of the scapula, it is evident that their 
analogy is to be found only amongst reptiles. Perhaps, 
then, we miglit say, that the scapula has a dorsal plate and 
acromial and coracoid processes ; that the acromial is to- 
lerably regular as to situation and distribution, but that 
the coracoid, which, in Man, is rudimentary, is, in the Or- 
nithorynchus, extended to the sternum *. We may next 
suppose the flat and broad portion of what I have hitherto 
called the clavicle, to be actually the anterior bone of the 
sternum ; which, in this view, would come to be composed 
of five instead of three bones, placed the one immediately 
behind the other -[-, whilst the two thin and long bones 
firmly united to the anterior extremities of them, might be 
considered as analogous to the merry-thought in birds |. 
But there still remain to be accounted for, the osseous 
squamous plates, articulated with what I have just called 
the coracoid process of the scapula, and which M. St. Hi- 
LATRE considers as analogous to a small process of bone found 
immediately at the base of the true clavicle in birds, and to 
• I ought to mention here, that that most excellent naturalist, M. Geof- 
raoY St Hilaire, considers the bone we call Clavicle in birds, as the cora- 
coid process of the scapula ; which idea is very beautifully supported by the 
form of the scapula in the Ornithorynchus. 
•\ The fourth of these, counting from the epigastrium, is constantly di- 
vided into two in the Ornithorynchus. 
X These are considered by M. Geoffroy as the acromial processes of the 
scapula greatly elongated. It is to be remarked, however, that they are con- 
nected to the scapula not hy bone, but by a very perfect moveable articula- 
tion, with a capsule,— and I am not sure that M. Geoffroy is aware of this 
fact. 
