126 'Journal of Comparative Neurology and Psychology. 

 The data from Boulenger give the following: 



TABLE 4. 



ESCULENTA. 



No. OF 



Specimens. 



Foot 



(Tarsus and 



Pes). 



44-1% 

 43-4% 

 45-9% 

 47-6% 



Variety rabibunda ' iM.+ iF. 



Variety rabibunda I F.* 



Variety typica I i M.+ 1 F. 



Variety lessonae i M. + 1 F. 



* Measured from Boulenger's Fig. loi, p. 280. 



In my Zurich series the individual measurements correspond 

 to those for the varieties rabibunda and typica as determined by 

 Boulenger. The average for these from the above table (4) is : 



Average Values for Varieties rabibunda and typica. 



Femur 27-0 



Tibia 28 . 3 



Foot 44-7 



And these values are close to those given for R. esculenta in 

 Table 3. 



For comparison in the case of R. temporaria, an average of two 

 determinations, one male, one female, by Boulenger is avail- 

 able. These give 



Femur ' 25.6% 



Tibia 28.4% 



Foot 46-0% 



M^hich is in fair agreement with the values given in Table 3. 



(6) In the relative length of the entire central nervous system 

 (that is, the length of the brain plus the length of spinal cord), in 

 relation to the total length of the frog. 



This relation is of course not a constant one, because the total 

 length of the frog increases more rapidly than the length of the 

 entire nervous system. To make the comparisons, therefore, 

 the percentages must be recorded in relation to the total length 

 found for each individual or group. The data used in this deter- 

 mination were the follow^ing: 



Ten (10) specimens of R. pipiens ranging in total length from 

 124 mm. to 185 mm. inclusive. The data being taken from the 



