128 ANIMAL LIFE PAST AND PRESENT. 



pelvis, although differing in some details, is, indeed, 

 of the general type of that obtaining in modern 

 crocodiles ; and thus serves to show that in this re- 

 spect the Megalosaur (and likewise the Hoplosaur) 

 were more nearly related to ordinary reptiles, and less 

 closely to birds, than is the case with the Iguanodon. 



If, however, we were led to conclude from the fore- 

 going facts that the Megalosaur presented no closer 

 indications of affinity with birds than is exhibited by 

 modern crocodiles, we should be grievously in error ; 

 for not only does it exhibit such a relationship, but 

 exhibits it in a manner which is not displayed by the 

 Iguanodon. In this respect we have, therefore, an 

 excellent illustration of that extreme complexity in 

 the mutual relationships of extinct animals, which 

 should serve as a warning against hasty conclusions 

 as to any one extinct type having been the actual 

 ancestor of an existing creature. 



The relationship of the Megalosaur to birds is best 

 exemplified by certain features in the form and con- 

 nection of the bones of the lower leg and ankle, in 

 attempting to explain which we must again crave the 

 reader's pardon for the introduction of a certain number 

 of unavoidable technicalities. 



Most of us are probably aware that our own ankle 

 consists of two rows of small bones, of which the 

 upper row includes the heel-bone, and the huckle-bone 

 (corresponding to the well-known " huckle-bone " of a 

 leg of mutton) ; while the lower row has four smaller 

 bones. Now in moving the foot on the leg, as in the 



