230 THE STORY OF BIRD-LIFE. 



girdle, but as the dinosaur has undergone less 

 change or specialisation in this region than the 

 bird, we may infer that the dinosaur's girdle 

 more nearly approaches the original clay from 

 Avhich each was modelled, so to speak. 



The scapula and coracoid certainly in their 

 general form and arrangement resemble the bird's. 

 But we get no merry-thought, and no sternum. 

 The former may have been lost, as it is in some 

 birds; the latter Avas probably never ossified, 

 but resembled that of the young penguin in 

 being cartilaginous and was, therefore, not pre- 

 served. In the penguin it ossifies late in life, in 

 the dinosaur not at all. The large size and num- 

 ber of the ribs in the dinosaur make it certain 

 that such a sternum once existed, for it is this 

 structure to the sides of which the ribs are 

 attached. The figures should make this clearer. 



Turning now to the hip-oirdle, we note equally 

 important points of resemblance, but upon the de- 

 tails of these we will not enlarge here. The chief 

 points of difference appear to be in the general 

 outline of the largest and U23permost of the three 

 bones of which this girdle is made up — and in 

 the greater size of the small forwardly projecting 

 spike of bone called the pectineal process. In 

 the bird this is never very large ; but as we said 

 before, we must not expect too close a resem- 

 blance. Indeed a very close resemblance would 

 rather prove too much. 



In the form of the hind-limb again, we have 

 one or two curious points of resemblance, that 

 would seem to imply kinship rather than simil- 

 arity of structure produced by a similar mode of 



