44 SHINKISHI HATAI 



This relation has been determined from the coefficients of 

 correlation and standard deviation given in his paper. We 

 assumed of course that the regression between the body length 

 and length of thigh, shank and foot is linear. This is admittedly 

 a crude method, nevertheless so far as we wish at the present 

 moment to determine the general features of the curves, such 

 simple treatment answers the purpose. 



We have however one important difference between the seg- 

 ments of Rana and those of Bufo, in the fact that in Rana the 

 length of the segment regularly increases towards the periphery, 

 while in Bufo, the length of the shank is least and that of the thigh 

 and of the foot stand in the order named. Thus in the toad if 

 the growth of the internodes is not at all influenced by the elonga- 

 tion of the segments, we shall find a progressive increase in the 

 length of the internodes towards the periphery, and the exponen- 

 tial law in this case will apply to the entire extent of the leg, 

 while on the other hand if the segmental influence is the main 

 determining factor, we shall find the shortest mean length of the 

 internode in the shank, and the exponential law in this case will 

 be applicable to each segment independently. 



Therefore the question of general segmental influence as the 

 main determining factor of the length of the internode in the differ- 

 ent segments, can best be tested from the internodes in the nerve 

 of the different segments in the leg of the toad. I hope to be 

 able to take up this question in the near future. 



BIBLIOGRAPHY 



Birge, E. A. Die Zahl der Nervenfasern und der motorischen Ganglienzellem in 

 1882 Ruckenmark des Frosches. Archiv.f. Anat. u. Physiol., Part 5 and 



6, pp. 435-570. 

 Boycott, A. E. On the number of nodes of Ranvier in different stages of the growth 



1904 of nerve fibers in the frog. J. of Physiol., vol. 30, pp. 370-3S0. 

 Davenport, C. B. Statistical methods. Second edition, New York. 



1904 

 Kellicott, Wm. E. Correlation and variation in internal and external characters 



1907 in the common toad (Bufo lentiginosus americanus, Le C.) J. of 



Exper. Zool., vol. 4, no. 4, pp. 575-614. 

 Takahashi, K. Some conditions which determine the length of the internodes 



1905 found on the nerve fibers of the Leopard frog, Rana pipiens. J. 

 of Comp. Neurol, and Psychol., vol. IS, no. 2, pp. 167-197. 



