INDIVIDUAL VARIATION.--In half the legs, the proximal end of the lateral head is notched for the passage of the peroneal nerve; the main part of the head lies medial to this nerve; the short fleshy slip lateral to this nerve arises by a long, slender, and extremely weak tendon from connective tissue surrounding the femorotibiotarsal joint. In one leg, a bundle of fibers separates from the lateral head and attaches to the terminal four mm. of the anterior (proximal) edge of the tendon of M. extensor iliofibularis. Each of the following variations occurs in several legs: a third dorsal slip on digit IV attaches to the distal end of the fourth phalanx in some legs and to the subarticular cartilage of the fourth joint in other legs; a third dorsal slip on digit III attaches to the distal end of the third phalanx in some legs and to the subarticular cartilage of the third joint in other legs; a second dorsal slip on digit II attaches to the distal end of the second phalanx in some legs and to the subarticular cartilage of the second joint in other legs. _T. cupido_ INDIVIDUAL VARIATION.--The dorsal slips of insertion show variations similar to those noted above for _T. pallidicinctus_. _P. p. jamesi_ INDIVIDUAL VARIATION.--In one leg, the proximal end of the lateral head is notched for the passage of the peroneal nerve. The dorsal slips of insertion show variations similiar to those given above for _T. pallidicinctus_. In four legs, a tiny vinculum extends from the lateral edge of the branch of the tendon on digit IV to the lateral edge of the underlying medial branch of the tendon of M. flexor perforatus digiti IV at the level of the second phalanx. =_M. Popliteus_=, Fig. 19B _T. pallidicinctus_ GENERAL DESCRIPTION AND RELATIONS.--Extremely short but relatively broad and thick; on posterior surface of proximal end of tibiotarsus; extending distomedially from proximal part of fibula; deep to M. flexor hallucis longus; lateral end overlapped by, and fused to, posterior head of M. flexor digitorum longus; medial end often slightly overlapped by, and fused to, M. plantaris; medial end (insertion) much wider than lateral end (origin). ORIGIN.--The origin is fleshy and tendinous (superficial surface) from the medial surface of the fibula near the proximal end. INSERTION.--The attachment is fleshy to the posterior surface of the proximal end of the tibiotarsus adjacent (lateral) to the origin of M. plantaris. INNERVATION.--A branch of the medial division of the tibial nerve penetrates the posterior surface. INDIVIDUAL VARIATION.--None of significance in any of the three species studied. =_M. Peroneus Longus_=, Figs. 12, 13 _T. pallidicinctus_