12 GUIDES FOR VERTEBRATE DISSECTION 



to the'knee, where it becomes tendinous and passes to its insertion 

 on the proximal end of the tibia. 



Just lateral to the gracilis minor is the gracilis major, crossed 

 by an oblique inscriptio tendinea. It arises from the pelvis and 

 is inserted, together with the minor, by two tendons, one going 

 to the proximal end of the tibia, the other to the hinder surface 

 of the tibio-fibula. Between the sartorius and the gracilis major 

 is the proximal end of the adductor magnus muscle. 



Sketch these ventral muscles; then cut through the sartorius 

 and both gracilis muscles and make out the following parts: 



Nearly the whole of the adductor magnus is now seen; note 

 its two heads, dorsal and ventral, arising from the ischium, and 

 trace its insertion on the distal end of the femur. 



Lateral to the proximal end of the adductor major a bit of the 

 pectineus muscle is seen and still farther to the outside the adduc- 

 tor longus, which crosses the proximal end of the crural. Separate 

 these, making out the origin of the pectineus from the anterior 

 part of the pelvic symphysis, and that of the adductor longus 

 from the lateral surface of the ileum. Their insertions, respectively 

 on the middle of the femur and on the tendon of the adductor 

 magnus, should be found. 



On the medial side of the adductor magnus is the slender 

 semimembranosus muscle arising by two heads. 



Sketch the three deeper muscles of the ventral side. There 

 are several smaller and deeper muscles which may be omitted. 



The largest muscle in the shank of the leg is the plantaris 

 longus, which arises by two heads, a larger one in the angle of 

 the knee, a smaller from the tendon of the triceps on the outside 

 of the knee. Below, the muscle passes into a long tendo Achillei 

 which passes over the 'heel' to the plantar surface of the foot. 



Lateral to this plantaris, as seen from above, is the peroneus 

 muscle, which arises from the convex side of the knee and is 

 inserted by two tendons on the distal end of the tibio-fibula. 



Add these muscles to the sketch of the dorsal superficial 

 muscles of the thigh. 



Turn the frog ventral side uppermost. The os cruris appears 

 in the middle line of the shank. The extensor cruris brevis is 

 attached to the proximal half of its lateral side, its origin being 

 on the distal end of the femur. On the medial side the tibialis 

 posticus is similarly attached to the os cruris. The tibialis anticus 



