342 DISCOVERY REPORTS 



To illustrate the variations likely to occur in the bodily proportions the tables on 

 pp. 340, 341 are drawn up in the same way as for Blue whales. The range of percentage 

 values for each measurement is divided into an arbitrary number of groups, and the 

 individual readings for each measurement for male Fin whales from South Georgia, 

 measuring from 20-00 to 21-99 m., and females from 21-00 to 22-99 m., are sorted out, 

 and the number which fall into each group are shown. 



The results are plotted in Figs. 76 to 95. 



A comparison between the charts illustrating the above tables with the corresponding 

 charts for Blue whales shows that the range of variation for each measurement corre- 

 sponds closely in the two species, and it will not be necessary to comment on the 

 separate measurements. 



It may also be said that, with the exception of No. 13 (anus to reproductive aperture), 

 all the curves approach as closely to the normal frequency type as one would expect 

 with the amount of data on which they are constructed, and it may therefore be con- 

 cluded that only normal variation occurs in these measurements. 



The explanation of the two maxima in the curve of measurement No. 13 for males 

 has been dealt with in the section on Blue whales. 



COLOUR 



The best description of the colouring of Fin whales from the North Atlantic, as of 

 Blue whales, appears to be that of True (1904), who gives a general account of the 

 features of the pigmentation of northern Fin whales and details of the colouring of 

 ten specimens examined by himself. Of southern Fin whales Barrett-Hamilton made 

 some brief notes on the colouring of thirty-nine whales examined by him at South 

 Georgia. 



The pattern of the pigmentation of southern Fin whales is perhaps more complex 

 than that of Blue whales, but there is probably less individual variation. The most 

 obvious feature is that pigment covers the whole of the back and flanks, while the 

 ventral surface remains unpigmented. This pigment is of a bluish slate-grey, varying 

 to some extent in tone and not at all unlike the groundwork colour of the skin of 

 Blue whales. As was pointed out by True and others, the tone rapidly deepens on 

 exposure to light and air until the skin becomes practically black. 



The flippers are in general pigmented on the outer and white on the inner surface 

 (though there may be a little pigment on the inner surface of the left flipper). The 

 white of the inner surface reaches round the rim of the lower border of the flipper, 

 and sometimes the tip is white dorsally. The upper surface of the tail flukes is entirely 

 pigmented, and the under surface is white except at the anterior and posterior borders, 

 where there is a margin of pigment. 



The most remarkable feature of the colouring of Fin whales is that the pigment is 

 arranged asymmetrically. This asymmetry is to be noticed on the outer ventral grooves, 

 the side of the head and shoulders, the under surface of the flippers, the upper and 

 lower jaws, the baleen, and inside the mouth. In reality it consists of a shifting of the 



