The top bone is the os calcis, or hock bone, to which the tendon Achilles is attached.
On the anterior or extensor surface of the limb a powerful tendon (7 in fig.
9, Tendon of deep flexor (fl.
14, The podophyllous or laminar 7, Tendon of anterior extensor membrane, and of the phalanges.
We have here the interesting fact that a muscle (portion of the triceps humeri of the reptiles) has been reduced to a tendon, which in a secondary way has become connected with cutaneous muscles, which, when strongly developed, represent its belly.