364 



GROWTH OF ORGANS IN RELATION TO BODY LENGTH 



by the Albino — ^save that the occipital cortex is relatively thicker 

 in the Norway. This difference appears to depend on the defective 

 development of the visual apparatus in the Albino. Table 196. 



TABLE 196 



A comparison of the cortical thicknesses at each locality and on the average, in the 

 adult Norwaij and the albino brains of the same absolute weight. The measure- 

 ments used here are average values of Groups NXVI-N XX and Groups XVI-XX 

 respectively, taken from tables 4 to 6 (Sugita, '18a) and tables 6 to S (Sugita, '17a). 

 The corresponding brain iveights are 1.844 grams in the Norway and 1.815 grams 

 in the Albino. The thickness of the Albino cortcv is always taken as the stand- 

 ard for computing the percentage differences 



5. Growth of the cerebral cortex in volume — wild Norway rat — 

 Sugita {^18 a). Employing the same initial measurements as 

 were made on the albino (p. 84) the relative volume of the 

 cortex in the Norway rat has been computed and in table 197 

 is compared with that in the Albino on the basis of hke brain 

 weights. 



