46 THE SALAMANDER 



the femur as its skeletal element; {b) the leg^ with the tibia z.rvAfibula\ 

 and {c) the /<2rjz/j and digits supported by the tarsals^ meta-tarsals^ and 

 -phalanges. As in the fore-limb all epiphyses and articular surfaces 

 remain cartilaginous. 



{a) The Femur (Figs. 3 1-3). The head of the femur is rounded 

 but not hemispherical, since there is a trochlear groove on its 

 postero-ventral surface which articulates with the ischial process on 

 the rim of the acetabulum, while the dorsal and antero-ventral sur- 

 faces are somewhat flattened and possess well-marked foveal de- 

 pressions (fv.c.fm.) wherein are inserted the ligaments attaching the 

 bone to the acetabulum (l.pb. and l.il.). In transverse section, there- 

 fore, the proximal end of the bone is roughly triangular, with the 

 sides facing dorsal, antero-ventral, and postero-ventral. There is 

 no neck, and the articular surface is terminal. There is a strong 

 hook-shaped trochanter (pr.tch.) directed antero-mesially on the 

 ventral surface, towards which, from either side of the trochlear 

 groove, run two trochanteric crests^ of which the posterior is the 

 less developed. The cross-section of the bone beyond the hook is 

 approximately circular but it soon expands into a rectangle of which 

 the long sides are dorsal and ventral . There are two articular condyles 

 distally, the pre-axial or tibial being the larger, although neither 

 is so pronounced as the corresponding surfaces of the fore limb. 

 The longitudinal axis of the bone is approximately straight when 

 seen from above, but shows a double curvature if viewed in an 

 axial direction. 



{b) The Tibia (o.tb.) is a straight simple bone whose section is 

 more or less rectangular at the ends and circular at its narrowest 

 part, which is at about one-third of its length from the distal end. 

 The long sides of the proximal end are on the flexor and extensor 

 surfaces, but at the distal end the long axis of the rectangle is at right 

 angles to these. A prominent /z^zW <:r(?j-/ (cr.tb. fig. 29) arises from 

 the dorso-mesial side of the extensor surface which finally becomes 

 independent of the surface of the bone so as to give it a thorn-like 

 appearance. It receives the insertion tendon of the M. extensor 

 ilio-tibialis. Distally the tibia articulates with the tibiale and inter- 

 medium. 



(c) The Fibula (o.f.) is a rather more slender bone than the tibia 

 but of about the same length. It is roughly triangular in section with 

 the base directed mesially. Its distal end is very oblique and articu- 

 lates with the fibulare and intermedium. 



{d) The Tarsus (Fig. 29 and 30). The fibulare (o.fb.) is the 

 largest of the proximal row of tarsal elements, and is not fused with the 



