300 Journal of Comparative Neurology. 



veys the chief mass of fibers to innervate the hind extremity, 

 and innervates the thigh, shank and foot. After giving off its 

 branches to the thigh it divides in the lowest third of the thigh 

 into the tibial and the peroneal nerves. The tibial nerve di- 

 vides just below the knee to form what are known as the rami 

 superficialis et profundus of the tibial nerve. The peroneal 

 nerve divides near the middle of the shank into the nervus 

 peroneus lateralis and the nervus peroneus medialis. 



The skin and muscles of the thigh, therefore, are inner- 

 vated by branches from the crural and the sciatic nerves ; the 

 muscles and skin of the shank by branches from the tibial 

 and peroneal nerves and their divisions ; and the tissues of the 

 foot by the terminal branches from the first and second sub- 

 divisions of the tibial and peroneal nerves. 



A. Coviparison of Rana viresccns ivttJi Rana escidetita a?td 

 Rana temporaria. 



In the previous study, Dunn, 1900, of the innervation of 

 the thigh, adoption was made of the nomenclature used by 

 Gaupp in his late edition of Ecker and Wiedersheim's Anat- 

 omy of the Frog, to identify the muscles and the nerve branch- 

 es. The same authority will be followed in the anatomical 

 nomenclature used in this paper. 



A comparison of the gross innervation of the thigh in 

 Rana virescens with that of Rana esculenta and Rana tempo- 

 raria revealed a few minor variations. A similar comparison of 

 the gross innervation for the shank reveals a correspondingly 

 small number of differences. 



Tables I and II are presentations in brief of the nerve 

 branches to the thigh and to the shank. 



Table I contains only the main branches of the crural and 

 sciatic nerves to the thigh, and the designations by which they 

 may be identified in Figure i. A more complete tabulation 

 with an accompanying figure may be found on pp. 220 and 22 L 

 of the preceding study, Dunn, 1900. 



