PHYSIOLOGIC APPARATUS. 



691 



Preparation of the Frog. Destroy the frog by plunging a pin through 

 the skin and soft tissues covering the space between the occipital bone and 

 the first vertebra until the point is stopped by the vertebra. Turn the 

 pin toward the head and push it into the brain cavity; move it from 

 side to side and destroy the brain. Pass the pin into the spinal canal 

 and destroy the spinal cord. With a stout pair of scissors cut off the body 

 behind the fore-limbs. Remove the viscera and the abdominal walls. 

 Draw the hind-legs out of the skin. Place the legs on a glass plate, back 

 uppermost, and moisten them freely with normal saline solution. 



FIG. 353. LEG MUSCLES or THE FROG. 

 VENTRAL SURFACE. (Ecker.} 



pc 



FIG. 354. LEG MUSCLES OF THE 

 FROG. DORSAL SURFACE. 

 (Ecker.) 



Observe on .the outer side of the dorsal surface* of the thigh the following 

 muscles (Figs. 353, 354). The triceps femoris (tr), made up of the rectus 

 anticus (ra), the vastus externus (ve), and the vastus internus (vi), not 

 seen from behind ; on the inner side, the semi-membranosus (sm) and the 

 rectus internus minor or gracilis (ri"). Between these two groups, note 

 the biceps femoris (b). Above the thigh observe the gluteus (gl), the ileo- 

 coccygeus (ci), and the pyriformis (p). 



In the leg observe the gastrocnemius (g) with its tendon (the tendo 

 Achillis), the tibialis anticus (ta), and the peroneus (pe). 



Turn the frog on its back and note the muscles on the ventral surface 

 of the thigh, the rectus internus major (ri'), and minor (ri"), the adductor 

 magnus (ad"), the sartorius (s), the adductor longus (aoV), and the vastus 



