BULBS OF THE FOOT. 51 



secreting or sensitive frog. The sensitive frog is much firmer 

 than the sensitive bulbs ; the elastic tissue being slight, the 

 tendinous or fibrous abundant in quantity. 



The inferior surface of the base of the l)ulbs and the postero- 

 inferior surface of the sensitive frog are divided by a cleft of 

 varying depth into two similar parts (tigs. 32, c, and 34, c). Above, 

 this conformation is continued in the bulbs (fig. 32, a). Anteriorly, 

 the two parts unite to form a level, pointed surface. The two 

 lateral surfaces are fiat, and marginate the limbs on either side. 

 They run towards the middle line of the foot, and meet at the 

 point of the plantar cushion (figs. 32 and 33, b). 



The cushion itself is fixed in position partly through the 

 medium of the elastic cords and tissues enumerated, partly 

 through its intimate connection with the lateral cartilages, but 

 chiefiy by the fibrous material which most intimately unites 

 the sensitive frog with the lower surface of the pedal bone. 



