SKULL OF THE BOA CONSTRICTOR. 81 



the nasal process of the premaxillary is received in the 

 interspace of the nasals. 



The acoustic capsule remains in great part cartilaginous ; 

 there is no detached centre of ossification in it ; to what- 

 ever extent this capsule is ossified, it is by a continuous 

 extension from the alisphenoid. The sclerotic capsule of 

 the eye is chiefly fibrous, with a thin inner layer of car- 

 tilage ; the olfactory capsule is in a great measure ossified, 

 as above described. 



MAXILLARY ARCH. 



The palatine, 20, or first piece of this arch, is a strong, 

 oblong bone, having the inner side of its obtuse anterior 

 end applied to the sides of the prefontals and turbinals, 

 and, near its posterior end, sending a short, thick process 

 upwards and inwards for ligamentous attachment to the 

 lachrymal, and a second similar process outwards as the 

 point of suspension of the maxillary bone. Between these 

 processes the palatine is perforated, and behind them it 

 terminates in a point. The 

 chief part of the maxillary, 21 

 (Fig. 14), is continued forwards 

 from its point of suspension, 

 increasing in depth, and termi- 

 nating obtusely; a shorter pro- 

 cess is also, as usual, continued skull of boa constrictor. 

 backwards, and terminates in 



a point. The point of suspension of the maxillary forms 

 a short, narrow, palatine process. A space occupied by 

 elastic ligament intervenes between the maxillary and the 

 premaxillary, 22, which is single and symmetrical, and 



