igo DISCOVERY REPORTS 



numbering has been retained, although some gaps are thereby introduced. The data 

 obtained are set out below and may be taken as a fairly good representation of the 

 external proportions of the Sei whales of South Georgia and an indication of those of 

 South Africa. There is no indication of any racial difference between the whales of the 

 two places ; the differences in the figures, where not due to inadequate numbers, are 

 to be explained by the higher proportion of immature whales in the South African 



catches. 



A summary of the analysis of the figures is shown in Table V, in which the measure- 

 ments, expressed as percentages of the total length, are given separately for males and 

 females from South Georgia, from South Africa, as totals, and for male and female 



foetuses. 



The only measurement which diflfers widely in the two sexes is No. 13, centre of anus 

 to centre of reproductive aperture; it is 27 times greater in males than in females. This 

 is due to the penis being more anterior in position than the vulva. The only other 

 measurement showing appreciable difference in the two sexes is No. 6, tip of snout to 

 tip of flipper, and is slightly greater in females than in males. The lengths of the flipper 

 do not differ materially in the two sexes, nor does measurement No. 3, tip of snout to 

 blow-hole : therefore the difference in measurement No. 6 must be due to the distance 

 between the blow-hole and the insertion of the flipper being slightly greater in the 

 female than in the male. This view is upheld by a consideration of measurements 

 Nos. 4 and 5, tip of snout to angle of gape and tip of snout to centre of eye, which show 

 a corresponding slightly greater proportion in females than in males. 



Tables VI, VII, VIII and IX show the manner in which the body proportions vary 

 with the size of whale. In these tables the mean value of each measurement for each 

 metre of whale length is given, together with the number of measurements producing 

 each mean value and the range of variation of each value. The figures are given as the 

 actual values in metres in roman type, and expressed as percentages of total length 

 in italic type. The figures expressed as percentages of total length are first discussed: 

 those of the actual values are dealt with in a later section of this report. 



The variations of the body proportions according to the length of the whale are 

 shown graphically for measurements Nos. 3-21 and 24 in Figs. 3-42, in which the 

 percentage value of the measurements is plotted against total length of the whale. The 

 curves for each sex are presented separately. Those derived from South Georgia whales 

 are distinguished from those derived from South African whales. In every figure the 

 curve for South Georgia whales is considerably more representative than that for South 

 African whales because it is derived from a much greater number of measurements. 



Although constructed from a fairly good number of measurements these figures are 

 all characterized by their great irregularity when compared with similar figures derived 

 from the measurements of Blue, Fin and Humpback whales. There appears, however, 

 to be no significant difference between the shapes of the curves for males and females, 

 nor between those for South Georgia and South African whales, except for measurements 

 No. 6, tip of snout to tip of flipper, and No. 13, the genito-anal distance, noted above. 



