1872.] MR. A. SANDERS ON LIOLEPIS BELLI. 177 



femur ; and its transverse section is triangular, with the base towards 

 the bone. 



Extensor longus digitorum (figs. 11 & 16) arises from the front of 

 the external condyle of the femur by a slender tendon, which passes 

 through a sort of groove between the heads of the tibia and fibula, 

 forming a fleshy belly in front of the leg ; it terminates in two 

 tendons inserted respectively into the peroneal side of the second and 

 third metatarsal bones close to their proximal extremities. This muscle 

 is remarkably like the radial extensors of the carpus ; its action is 

 more that of a flexor of the foot than an extensor of the digits. 



Tibialis anticus (figs. 8, 11, & 14) arises from rather more than 

 the proximal half of the front, and from rather less than the distal 

 half of the internal surface of the tibia, and is inserted into the inner 

 side of the base of the metatarsal bone of the hallux ; it further sends 

 a tendon to be inserted into the tibial side of the same metatarsal 

 bone for half its length. 



Peronceus primus (fig. 11) arises from the outer condyle of the 

 femur by a narrow tendon, separated from the flexor perforatus by 

 the insertion of the biceps, over which it passes ; in the leg it forms 

 an elegantly shaped muscular mass, and is inserted into the flat 

 surface on the dorsum and peroneal edge of the cuboid in proximity 

 to the base of the metatarsal bone of the fifth digit. The inner edge 

 of its tendon spreads out over the end of the fibula, receiving a mus- 

 cular insertion from the tibialis posticus, and joins the under surface 

 of the tendon of the perforans. 



Peronceus secundus (fig. 11) arises from the head and the whole 

 length of the outside edge of the fibula in front of the last, and is 

 inserted into the posterior edge of the cuboid bone of the tarsus. 



Gastrocnemius (fig. 8) appears to be represented only by the inner 

 head of that muscle ; it arises from the inner edge of the proximal 

 fourth of the tibia, and from the inner condyle of the femur, covered 

 by the insertions of the sartorius, gracilis, and semimembranosus. At 

 its origin it receives a tendon from the pyriformis, as above men- 

 tioned, and is also attached to the interarticular cartilage of the knee- 

 joint ; it ends in a thin flat tendon, which, passing over the tarsus, 

 is inserted into the base of the metatarsal bone of the fifth digit. 



Flexor perforatus digitorum (figs. 8, 11, & 14) arises from the 

 outer condyle of the femur by a strong but narrow tendon, which 

 has also an attachment to the pyriformis tendon and to the inter- 

 articular cartilage of the knee-joint. This muscle forms a thick fleshy 

 mass, having on its superficial aspect a groove for the last, which on 

 passing the tarsus becomes covered by a strong broad tendinous 

 expansion. The deeper muscular layer is partly inserted into the 

 tuberosity on the inner side of the cuboid bone, while the superficial 

 tendinous expansion is inserted by its edge to the outer side of the 

 same bone, aud by its distal extremity to the heads of the third and 

 fourth metatarsal bones, and, besides, gives three tendons to the 

 latter digit — one being attached to the base of the second phalanx, 

 one to the base of the third (this splits for the passage of the per- 

 forans tendon), and another to the base of the fourth phalanx, so that 



Proc. Zool. Soc— 1872, No. XII. 



