210 ELEMENTARY BIOLOGY. [XIIL 



d. In front of the end of the blade of the para- 

 sphenoid and of the palatines are two broad 

 irregularly shaped bones, each bearing an oblique 

 row of teeth on its posterior part : these are the 

 vomers. 



e. The middle anterior boundary of the contour of 

 the skull, in this view, is formed by the denti- 

 gerous parts of the pre-maxiUse; and, behind 

 them, by the maxillae and the quadrato-jugal bones 

 (4. a. b). Kunning backwards from the outer 

 end of the palatine, and closely applied to the 

 maxilla, is a bone, which soon separates from the 

 maxilla, and becoming broad and stout, bifurcates; 

 the inner process nearly joins the parasphenoid 

 and is moveably articulated with the skull ; the 

 outer runs along the inner face of a cartilage (the 

 suspensorium), on the outer face of which the squa- 

 mosal rests : this is the pterygoid bone. 



At the outer edge of each vomer, immediately 

 in front of the palatine, is an aperture which 

 leads into the nasal cavity. These two apertures 

 are the posterior nares. 



4. The side of the skull. 



a. Running back from that part of the pre-maxilla 

 which bounds the gape is a long bone, forming 

 almost the whole of the rest of the upper edge of 

 the gape ; this is the maxilla. 



b. Joined to the posterior end of the maxilla is a 

 small bone, which at its posterior end is attached 

 to the distal portion of the squamosal. This is 

 the quadrato-jugal. 



