262 OX THE STRUCT UK E OF THE SKULL. 



The premaxilke enter largely into the composition of both 

 the upper and under regions of the snout. As has been already 

 stated, they unite in front of the nasal bones, so as to exclude 

 the latter from the anterior nares, as is the case in some Croco- 

 dilia. The maxillary bones send horizontally inwards a broad 

 and long palatine process. This, like the corresponding process 

 of the palatine bone, is separated from its fellow in the middle 

 line, for some distance, by the vomer. On the left side of the 

 specimen from which this description is taken there is a distinct 

 large triangular lachrymal (Fig. 101) ; it is imperforate, and 

 situated altogether upon the side of the face. An oblique suture 

 extends downwards and forwards from that which separates this 

 lachrymal, inferiorly, from the adjacent bones, and seems to mark 

 off the jugal from the maxillary bone. On the right side neither 

 this suture exists, nor oxiy indication of a distinct lachrymal. 



The essential characters of the Proboscidean cranium are 

 best displayed in the foetal Elephant, as the sutures become obli- 

 terated, and the true form of the skull is disguised by the 

 enormous development of the air-chambers between the tables 

 of the skull, in the adult. 



Fig. 103 represents the longitudinally and vertically bisected 

 skull of such an Elephant. The whole basi-cranial axis is 

 slightly concave upwards. The basi-occipital and the basi- 

 sphenoid, the presphenoid, and the ethmoid are already so com- 

 pletely anchylosed that the traces of their primitive distinctness 

 have almost disappeared. On the other hand, the presphenoid 

 and the basi-sphenoid are widely separated by the remains of a 

 synchondrosis. The occipital angle is about 90°, the olfactory 

 angle 160° to 170°. 



The frontals enter as much into the front wall as into the 

 roof of the skull, and extend largely down upon its sides. An- 

 teriorly and externally they are prolonged into great arched 

 supra-orbital processes, which form the roofs of the orbits. 



The parietals are narrower in the middle line of the vertex 

 than anywhere else, being encroached upon by the frontals, 

 anteriorly, and by the supra-occipital behind. Infero-laterally, 

 the parietals widen out very much and extend far down into tin- 



