AYES. 83 



termination of the spinal cord are given to the muscles and skin of the cloaca and 

 tail. In the swan the anterior crural nerve is formed by the first, second, and third 

 lumbar nerves, and is accompanied by a small artery ; it is given to the muscles which 

 are in the place of the gluteal, the tensor of the fascia of the thigh, the straight muscle, 

 the external and internal vast, and the crural, and sends off a slender branch, the 

 saphenus, to be joined by another from the obturator to pass down on the inner side of 

 the leg. The obturator nerve arises from the second and third lumbar nerves, and 

 after giving off the branch to join the saphenus, terminates on the obturator and 

 pectineal muscles. The sciatic nerve arises from six nerves below the third lumbar, 

 and is accompanied by the femoral artery into the thigh ; after giving branches to the 

 adductor and the flexors at the back of the thigh, which are in the place of the biceps, 

 the semimembranous, and semitendinous, it passes down and divides into the posterior 

 tibial and peroneal nerves. The posterior tibial divides into two portions ; one gives 

 branches to several muscles corresponding with the inner part of the gastrocnemius, 

 the posterior tibial, and the flexors of the toes, and sends one down to the skin at the 

 inner side of the leg ; the other portion is given to the heads of the muscles forming 

 the outer part of the gastrocnemius. The peroneal sends a branch down the leg 

 behind the tendons towards the outer malleolus, and from thence to be distributed on 

 the sole of the foot : the course of this corresponds with that of the posterior tibial in 

 mammalia. The peroneal passes to the outer side of the leg, and gives branches to 

 the muscles corresponding with the peroneal, the anterior tibial, and the extensor of 

 the toes ; it gives off the anterior tibial, which passes between the peroneal muscle and 

 the extensor of the toes, and under the annular ligament, and gives a branch to the 

 inner side of the first or inner toe, and another to divide for the outer side of the first 

 toe, and the inner side of the second. The continuation of the peroneal becomes 

 superficial about the lower part of the leg, and passes over the annular ligament at the 

 ancle, and then between the tendons of the second and third toes, and divides for the 

 outer side of the second and the inner side of the third ; another slender branch passes 

 from between the muscles on the outer side of the leg, and is distributed on the skin 

 about the outer ancle. 



M 2 



