Dunn, Innervation of the Thigh in the Frog. 223 



nerve, as is represented in Figure I. This branch is disregarded 

 in all our computations because it is not concerned in the inner- 

 vation of the muscles of the thigh. 



b. The branch to the M. pyriformis (S 2) is given off with 

 the R. cutaneus femoris posterior (S 3), and takes its departure 

 from the latter at the point where the cutaneous branch passes 

 under the M. pyriformis on the way to its peripheral distribu- 

 tion. In no instance was it found arising directly from the 

 trunk of the sciatic nerve, as occurs in Rana esculenta. 



c. The branch to the M. ileo-fibularis springs from the 

 sciatic trunk proximal to the R. profundus anterior, or springs 

 as a subordinate branch from this ramus. In no dissection was 

 it found springing from the sciatic trunk distal to the R. pro- 

 fundus anterior, the condition pictured in Rana esculenta.^ 



d. The second branch to the caput ventrale of the M. ad- 

 ductor magnus, given in broken lines in Figure I, and desig- 

 nated (S 6 b i) /J ) is absent in Rana virescens. The anterior and 

 terminal portion of the R. descendens communis from which 

 this branch is given off in Rana esculenta passes over the M, 

 adductor magnus in order to reach the M. sartorius, but no 

 branch to the former muscle was found in Rana virescens. 



e. In the ten dissections examined, the branches to the M. 

 gemellus and the M. obturator internus were found to come 

 from a common stem, whereas in Rana esculenta they more 

 frequently arise independently. 



B. Review of the accounts of the innervatioji of the thigh which 



are given in successive editions of Ecker 's Anatomy of the Frog. ^ 



As the successive editions of Ecker's Anatomy of the Frog 



show wide variations in the nomenclature and innervation of 



the muscles of the thigh, and the recent edition of Gaupp, 



* See Figure 56, Gaupp's edition, p. 195. 



^ (a) Die Anatomic des Frosches. Dr. Alexander Ecker. Braunschweig, 



1864. 

 (b) The Anatomy of the Frog. Dr. Alex. Ecker, translated and revised 



by George Haslem, M.D., Oxford, 1889. 

 (b) A, Ecker's and R. Wiedersheim's Anatomie des Frosches, edited by 



Dr. Ernst Gaupp. Braunschweig, 1896-99. 



