296 



MAMMALIAN ANATOMY 



FIG. 214. 



-Palatine 



from the cribriform plate behind. Each mass consists of a narrow 

 plate with a scroll above and a scroll below. A transverse section of 

 the mass may be represented diagrammatically thus, ~|j. With one 



exception (Figs. 214, 219, 

 m), no partitions appear 



fl^^^39^k. "" the inner surface of 



^Wf, **) /^wWMk 



1 X/yjp^B^ the lateral ethmoid, as 



~/i / / fvL) that surface is for the 



i// ^") H 



\!^~^J^)jf most part not attached to 



^^L^ yV m the median plate of the 



frontal nor to the meseth- 

 moid which it faces. The 

 fourth pair of scrolls is 

 expanded in front, form- 

 ing first the floor of the 

 cleft, and then, splitting 

 up into thin plates, be- 

 comes, still further for- 

 ward, the smaller part of 

 the external surface of the 

 lateral ethmoid. They 

 are also seen at the ante- 

 rior end of the inner sur- 

 face, but, as there is no 

 cleft on this surface, the distinction is at first not so obvious. 



The smaller part of the external surface (Figs. 211, 215) which 

 lies anterior to the vertical cleft is triangular in outline. The shorter 

 upper border is directed downward and forward ; the lower border 

 is directed downward and backward, and is emarginate to fit over the 

 maxillo-turbinal ; the posterior border, which is about as long as the 

 lower border, is also directed upward and forward, but more vertically, 

 forming nearly a right angle with the superior border. The triangle 

 is composed of many scrolls, which differ from the posterior scrolls in 

 being narrow, delicate, and pressed close together ; they also differ in 

 being directed upward and forward. They are attached below and 

 behind and are free in front and above. Their upper ends curve 

 downward. 



The superior surface (Fig. 215) of the lateral ethmoid is long and 



TRANSVERSE VERTICAL SECTION THROUGH HALF OF FACE. 



Three millimetres anterior to central part of cribriform plate of 

 ethmoid. Cut surfaces black (somewhat diagrammatic). 



