333 DISCOVERY REPORTS 



Graphical representations of selected measurements from the foregoing tables are 

 shown in Figs. 53 to 75, and it will be seen that in general the results are very similar 

 to those which appear in the case of Blue whales. There is no important difference 

 between the curves for the two sexes, except of course in the case of measurement 

 No. 13, and though a slight distinction appears between Fin whales of South Georgia 

 and South Africa, which will be dealt with immediately, there is no difference between 

 the shapes of the curves. 



As in Blue whales, the anterior measurements (Figs. 53 to 62) show a relative increase 

 as the whale-length increases. The increase is about 0-45 per cent per metre of whale- 

 length as the whale-length increases from 14 to 22 m. The measurements referring 

 to the posterior part of the body show a corresponding decrease. 



A feature of the anterior measurement which is very noticeable in female Fin whales 

 and is distinguishable in males (and, incidentally, in Blue whales of both sexes), is 

 that the curves for South African whales fall in advance of the curves for South Georgian 

 whales, to which, however, they correspond in shape. This means that the South 

 African whales have relatively larger heads than those of the same total length at South 

 Georgia. In Fin males the difference is about 0-7 per cent of the whale-length and in 

 females about o-8 per cent of the whale-length. 



Among the posterior measurements we find that the female Fin whales again show 

 a South African curve in advance of the South Georgian curve, which means that the 

 South African whale has a relatively smaller tail than the South Georgian whale of 

 the same size. In male Fin whales and Blue whales of both sexes this difference is 

 not noticeable. 



As grovs^h is accompanied by a relative increase in the size of the head and a relative 

 decrease in the length of the tail, one may say that the South African whales (female 

 Fin whales especially) have heads and tails whose proportions correspond with whales 

 I to 2 m. longer at South Georgia. 



If the attainment of physical proportions goes on to some extent independently of 

 growth in length, whales of the African coast would appear to be stunted and 

 their smaller size accentuates the relatively increased size of the head and decreased 

 size of the tail, while at South Georgia exactly the opposite happens. In support of 

 this interpretation it may be pointed out that in the graphs of the anterior measure- 

 ments a maximum head size is reached in Fin whales of South Africa at about 

 19 to 20 m. and the curve then drops to the level of the South Georgian whales which 

 reach the maximum at about 23 m. 



It is possible that this difference in the bodily proportions of South Georgian and 

 South African whales is due to a slightly emaciated condition among the latter, caused 

 by the relative scarcity of food. 



As to the other measurements illustrated in Figs. 71 to 75, we find no difference 

 between the whales of the two localities in respect of measurement No. 13 (Fig. 71) 

 or of measurements Nos. 17 and 18 (Figs. 72 and 73), but the depth of the tail (Figs. 74 

 and 75) is again slightly greater in South Georgian whales. The size of the whale appears 

 to make no difference to this measurement. 



