INNERVATION.--One or more branches of the peroneal nerve enter the lateral edge. INDIVIDUAL VARIATION.--In four legs, the lateral branch of the trifurcated tendon is not ossified at all. _T. cupido_ INDIVIDUAL VARIATION.--In a few cases, the muscle does not come in contact with M. peroneus brevis. _P. p. jamesi_ DIFFERENCES FROM TYPICAL _T. pallidicinctus_.--The belly is shorter. The lateral branch of the tendon on the tarsometatarsus is not ossified (true also of some legs of _Tympanuchus_). INDIVIDUAL VARIATION.--In several legs, the muscle also arises from the distal part of the posterior surface of the outer cnemial crest. =_M. Peroneus Brevis_=, Figs. 14, 16, 17, 18, 19A _T. pallidicinctus_ GENERAL DESCRIPTION AND RELATIONS.--Small; on lateral surface of distal part of tibiotarsus; mainly anterior to fibula; bounded posteriorly and laterally by M. flexor digitorum longus (fused with latter), anteriorly by M. tibialis anticus, and anteromedially by M. extensor digitorum longus (usually slightly fused to latter). ORIGIN.--The muscle arises by fleshy and tendinous fibers from the medial and anterior surfaces of the fibula beginning a short distance below the distal end of the fibular crest and from the anterolateral surface of the tibiotarsus anterior to the fibula; the anteromedial edge attaches to the anterolateral intermuscular line. INSERTION.--The short, slender, ossified tendon passes along the anterolateral surface of the tibiotarsus and through a retinaculum immediately proximal and anteromedial to the retinaculum for the anterior branch of the tendon of M. peroneus longus; the tendon becomes flexible and widens as it passes across the lateral surface of the intratarsal joint deep to the tendon of M. peroneus longus, turning posteriorly and attaching to the proximolateral corner of the hypotarsus. INNERVATION.--The superficial peroneal branch of the peroneal nerve gives one or two twigs to the anterior surface of the proximal part. INDIVIDUAL VARIATION.--None of significance. _T. cupido_ INDIVIDUAL VARIATION.--In a few legs, the muscle does not come in contact with M. extensor digitorum longus. _P. p. jamesi_ INDIVIDUAL VARIATION.--None of significance. =_M. Extensor Hallucis Longus_=, Figs. 19E, 20N _T. pallidicinctus_ GENERAL DESCRIPTION AND RELATIONS.--Slender and elongate; proximal part on anterior surface of tarsometatarsus medial to anterior metatarsal groove; near midlength of tarsometatarsus, muscle twisted onto medial surface of latter; divisible into two heads--proximal and distal; belly of proximal head (largest) ending at level of twisting onto medial surface of bone; short distal head beginning at this point deep to tendon of proximal head and soon joining latter tendon.