296 ELEMENTARY PHYSIOLOGY. [XXVIIL 



an aperture over the foramen rotundum; this 

 arrangement is a characteristic of the Felidse ; 

 break through the bone from above and very 

 carefully remove it in pieces with forceps. The 

 rest of the cavity of the tympanum is thus ex- 

 posed. 



Note the funnel shape of the membrana tym- 

 pani; it has the handle of the malleus attached 

 to it; this proceeds from the outside attachment 

 of the membrane slightly upwards to a little past 

 the middle point of the membrane (cp. foot-notes, 

 p. 295). 



4, Running out from a bony rim behind the mem- 

 brana tympani in the outer part, will be seen a 

 band of tissue stretching to the outer, anterior 

 edge of the bony rim surrounding the foramen 

 rotundum; from this a thin ligament proceeds 

 at right angles to the former band to be inserted 

 into the head of the malleus. This is the 

 posterior ligament of the malleus. 



5, On the opposite side of the head of the malleus 

 and in the same straight line, note the processus 

 gracilis running down to the lower edge of the 

 membrana tympani; it is attached here to the 

 bony wall by the anterior ligament of the 

 malleus ; do not attempt to trace the ligament 

 till the malleus is removed later on. The tissues 

 in the straight line thus followed down form the 

 axis band of the malleus, i.e, the axis about 

 which the ossicula auditiis turn. 



