594 B. F. Kingsbury and H. D. Eeed. 



lage of the car capsule, so that doubtless this is a variable feature. 

 In the adult there appears to be a very slender cartilaginous connec- 

 tion. The portion of the fenestra vestibuli not occupied by the 

 columella is thus a crescent of somewhat horse-shoe shape. 



The stilus of the columella arises gradually from the cephalic half 

 of the fenestral plate, passing at first more laterally and then in a 

 curve cephalad and slightly dorsad to become closely attached to the 

 lower edge of the squamosum. In its course it passes between the 

 vein and artery, as is typical, the vein being above (PI. VII, Fig. 

 51). The facial nerve is entirely ventral to it, though the jugular 

 branch and ramus communicans IX come very close, the latter lying 

 at first upon the dorsal side of the columella ; it slips over the outer 

 side, however, and joins the R. jugularis in gliding under the stilus 

 just as the latter joins the squamosum. 



The sheet of fascia covering the inner surface of the M. cephalo- 

 dorso-mandibularis possesses two thickenings of morphological 

 importance. The more dorsal of these (Ligamentum hyo-columel- 

 lare) arises over the outer side of the ceratohyal, curves around its 

 upper surface and passes forward to join the stilus columellse at its 

 bend and, as a sheath upon its outer side, accompanies the latter to 

 its articulation with the squamosum. Fig. 51 (PI. VII) illus- 

 trates the location of this ligament in its course from hyoid to 

 columella and shows the muscle "bellying against" the ligament as 

 a full sail against a rope. A portion of this seems to have been 

 Parker's stapedio-suspensorial ligament. The more ventral and 

 band-like ligamentous thickening passes from the ceratohyal to the 

 caudal edge of the quadrate. It cun^es around this element and a 

 portion of it joins the tendon of the M. cephalo-dorso-mandibularis 

 at its insertion on the os angulare. This ligament must embody the 

 ligamentum hyo-suspensoriale and as well the ligamentum hyo- 

 mandibulare. In connection with the former, in the adult is devel- 

 oped the cartilaginous process of the palatoquadrate already 

 described. Whether this process develops from an independent 

 center or not, and at what stage it appears, cannot be determined 

 from the material at hand. 



In the larva, the suspensorium has not the "rotated" position that 



