44 8 



DISCOVERY REPORTS 



whale — or rather, possibly, to the amount of space available in the body cavity, which 

 will, indeed, be dependent on the animal's girth. A Blue whale has a considerably 

 greater volume than a Fin whale of the same body length. 



It must be remembered, however, in considering these measurements, that there is 

 immense variation in the dimensions of the kidneys, and that these figures are averages 

 and are thus only representative for body lengths for which the greatest number of 

 measurements has been taken. For Fin females these lengths are 20-0, 21-0 and 22-0 m. 

 and for Fin males 18-0, 19-0, 20-0 and 21-0 m. Among Blue whales the numbers of 

 kidneys examined for each body length were small, so that the measurements are less 

 representative than those for Fin whales. The extent of the variations which may occur 

 are illustrated by the following eight measurements taken at random from the measure- 

 ments of the kidneys of female Fin whales of 22-0 m. body length (left kidney only). 



It is seen that in general an excess in one dimension is compensated for by a deficiency 

 in another and vice versa. The depth appears to be the most constant measurement. 



No sex differences in the dimensions of the kidneys were discernible either in Blue or 

 Fin whales. 



In Tables I A and II a the proportions of the kidney are shown worked out as ratios 

 of length : breadth : depth and of length : breadth. These ratios, again, are only 

 representative for those body lengths for which the greatest number of measurements 

 was made. The length-breadth-depth ratio shows that, compared with the depth, 

 which is seen by Tables I and II to be fairly constant, by far the greatest increase 

 takes place in the length of the organ— the ratio of the length to depth undergoing a 

 fairly steady and appreciable increase. The ratio of the breadth to the depth increases 

 less markedly. In general, however, the proportions of the kidney remain fairly 

 constant, and the ratio length-breadth remains remarkably constant throughout the 

 series. In relation to the depth the length of the organ seems to show a greater 

 individual variation than the breadth. The length of all kidneys, both Blue and 

 Fin, is about three times the breadth. The proportions of the kidneys of Blue and Fin 

 whales are very similar. For females of both species the average ratio is : 

 Length : breadth : depth ... 7:3:1 

 Length : breadth ... ... 3 : 1 . 



In order to compare the sizes of kidneys with one another, an index of size was 



