608 



Mr. W. P. Pvcraft on the 



sitta replaced by a narrow horizontal slit opening rather 

 higher than the level of the top of the normal aperture, and 

 only a little below tlie level of the posterior canthus of the 

 eyelid. It extends forwards on to the eyeball and backwards 

 on to the skull, its width exceeding the width of the eyelids. 

 Opening horizontally it appears normally to be closed like 

 the pocket of a coat. The chamber to which it gives access 

 is, when explored with a probe, found to be capacious, 

 extending downwards to the level of the quadrato-jugal bar, 

 forwards to the gape, and backwards to the extreme hinder 

 angle of the lower jaw. 



Text-fig. 37. 



A. Left side view of head of Acanthidositta chloris, to shew the form of 

 the nostrils and the remarkable aperture of the ear after removal of 

 the outer skin. 



1!. Shewing the interior of the aural chamber after cutting away its 

 outer wall. 



na. = nostril ; a.it. = aural aperture (slightly forced open); e. = eye ; 



_/.=ja\v. The arrow in the lower 6gure denotes the passage to the 

 middle ear. 



After removal of the outer skin, it is clear that this pocket 

 is formed by the expansion of the normally invaginated skin 



