678 



REPTILIA. 



the head of the Crocodile, or indeed of most Eeptiles, the anatomist finds 

 his studies much facilitated by the circumstance that the sutures sepa- 

 rating the individual bones never become obliterated, so that the ele- 

 ments of this portion of their skeleton remain permanently detached 

 and separate ; and for this reason we shall take the present opportunity 

 of going a little into detail concerning the composition of the skull of 

 the Crocodile, as it is well calculated to illustrate the real structure of 

 the cranium in the Vertebrata generally. 



(1889.) The bones belonging to the face are easily recognized : the 

 intermaxillary (17), the maxillary (18), and the nasal (20), the zygo- 

 matic (), and the lacrymal (c), all occupy their usual relative positions. 

 The roof of the mouth is formed, as in Man, anteriorly by an elongated 

 process of the upper jaw (18), and posteriorly by the palate-bone (22). 

 (1890.) The frontal consists of five pieces, viz. the principal 

 frontal (l), which probably, in the foetus, consisted of two lateral halves, 

 the anterior frontal (2,2) and the posterior frontal (4, 4). 



Fig. 332. 



.Skull of the Crocodile. 



(1891.) The parietal (7) is, as is generally the case in Reptiles, 

 represented by a single bone. 



(1892.) The occipital consists of four pieces, which remain perma- 

 nently detached ; namely, the basilar (5), the two lateral occipital (10), 

 and the superior occipital, placed above the foramen magnum. 



