THE IlfTEENAIi SKELETOIS-, l8l 



bone (which articulates with the inner aspect of the quadrate) 

 and the end of a quadrato-jugal bone (which articulates with 

 the outer aspect of the quadrate). 



The median and inferior bar of bone is the most irregular 

 in form and altogether the most inconstant of the sis. It is 

 formed of a bone, called the vomer, generally single, but which 

 may be double (two side by side), extending from beneath the 

 anterior part of the rostrum, forwards towards the middle part 

 of the premaxUla, with which it is often connected by soft 

 tissue only. 



The two organs of smell are situated one on either side 

 within the facial part of the skull, being sheltered and more or 

 less protected by the bony framework of the bill. A scale- 

 like bone, called the nasal, roofs over the hinder part of each 

 nasal cavity, and forms the hinder margin of the nasal aperture. 

 This bone consists of a posterior body and two forwardly 

 extending and diverging limbs, the angle between which may be 

 more or less acute or may be rounded. When it is rounded, and 

 a line, joining the most backward point of the margin of the 

 nasal of one side with that of the other, passes in front of the 

 hindmost end of the median backwardly extending branch of 

 the premaxilla, such a nasal is called holorhinal. If the angle is 

 acute, and the same transverse line does not pass in front of the 

 hinder end of the median branch of the premaxilla, then such a 

 nasal is called schizorhinal. Extending outwards on either side 

 of the median, ascending branch or process of the premaxilla, 

 external to each nasal, another bone called the lachrymal is 

 placed at the front margin of the orbit. Within it is a bone, 

 bounding the orbit in front, called the lateral ethmoid. The 

 anterior part of the interorbital septum is called the median 

 ethmoid. At the hinder margin of the orbit there is a more 

 or less prominent process called the postfrontal. 



Eeturning to consider the cranium proper, or brain-case, it 

 may be noted that the hole mentioned as permitting the 

 junction of the brain and spinal marrow is called the foramen 

 magnum. It is also called the occipital foram,en, because the most 

 posterior region of the skull is called the " occipital " region. 

 Immediately beneath the foramen magnum is a spheroidal pro- 

 minence which fits into the depression on the front of the atlas 

 vertebra already described. This prominence is called the occi- 

 pital condyle. The bones which enclose the internal ear are 

 called periotic, but they are not separate from the parts of the 



