VERTEBRA OF THE CROCODILE. 108 



It is very true, as Cuvier said in the last lecture he de- 

 livered, "if we were agreed as to tlie crocodile's head, we 

 should be so as to that of other animals ; because the 

 crocodile is intermediate between mammals, birds, and 

 fishes." Accordingly, the following description of the 

 crocodile's skull is coextensive with that of the fish; if 

 the answerable bones are rightly determined between 

 these, their correspondence with those of other verte- 

 brates will be facilitated. The difliculties in comprehend- 

 ing the nature of some of the bones of the crocodile's 

 head have arisen through passing to its comparison from 

 that of the mammal's skull — by descending instead of 

 ascending to it. 



The segments composing the skull are more modified 

 than those of the pelvis; but just as the vertebral pattern 

 is best preserved in the neural arches of the pelvis, which 

 are called collectively "sacrum," so, also, is it in the same 

 arches of the skull, which are called collectively "cra- 

 nium." The elements of which these cranial arches are 

 composed, preserve, moreover, their primitive or normal 

 individuality more completely than in any of the vertebrre 

 of the trunk, except the atlas, and consequently the arche- 

 typal character can be more completely demonstrated.* 



If, after separating the atlas from the occiput, we pro- 

 ceed to detach the occipital segment of the cranium from 

 the next segment in advance, we find the detached seg- 

 ment presenting the form and structure of the neural arch. 

 The " centrum" presents, like those of the trunk, a con- 

 vexity or ball at its posterior articular surface, but its 

 anterior one, like the hindmost centrum of the sacrum, 



' The skull of the crocodile, partially disarticulated, and "with the 

 bones numbered as in the following description, may be had of Mr. 

 Flower, No. 22 Lambeth Terrace, Lambeth Road. 



