4o6 DISCOVERY REPORTS 



those for which actual weights are recorded. Mackintosh and Wheeler {Discovery 

 Reports, l, pp. 296-7) have shown that in actual fact some alteration takes place, 

 but it is so small that it makes very little difference to the validity of the weights shown 

 in Fig. 4. In this figure three curves are shown, each based on one whale: curve A on 

 a whale of 20-3 m., 48-9 tonnes (without blood); curve B, 27-18 m., 122 tonnes; curve 

 C, 2378 m., 617 tonnes. The theoretical weight of the whale of 20-3 m., as found on 

 curve B, approximates very closely to its actual weight, as does also that of the whale 

 of 27-18 m. There is less agreement between these curves and curve C (Lucas's whale). 

 The blubber content of this whale was very low, only 12-8 per cent of the total weight 

 against an average for the first two whales mentioned of 19-83 per cent. It is to be sup- 

 posed that this whale, in any case different from the others in being a Northern Blue, 

 was in poor condition and that its weight was low for its length. On the whole, the 

 mean of curves A and B may be taken to furnish an approximate guide to the weights 

 of Southern Blue whales. 



