364 



DISCOVERY REPORTS 



may be really composed of two groups, and the younger of these groups is from the 

 appearance of the graph composed of somewhat smaller whales than the older. This to 

 some extent corroborates the inference that two groups are present. The mature whales 

 with two age series of scars can be explained on the assumption that they missed a north- 

 ward migration, or alternatively, that they made a prolonged stay in the north so that 



in 



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 _J 

 < 



X 



15- 



in 



tt 10 

 w 



m 



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 2 



U. 



o 



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25 



U 



z 



W 



D 

 3 



uj 2Q 

 a. 



10- 



5- 



ONE AGE-5ERIE5 



TWO AGE- 5ERIE5 



THREE AGE-SERIES 



FOUR AGE-SERIES and OVER 



13 



14 



15 



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16 



~T 



— r- 



17 



~r 



SEXUALLY 



LENGTH 

 IMMATURE O— 



— 1— 

 IB 



IN 



T 



T 



— 1 — 



20 



T 



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21 



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19 

 METRE5 



SEXUALLY MATURE 



— 1 — 

 22 



— 1 — 

 23 



E4 



Fig. 3. Fin whales, females. South Georgia, 1929-30. Length frequency in half-metre length groups and 



number of age series of scars. 



it is difficult to tell where an older scar series left off and a newer one began. It is, in 

 fact, possible to find a feasible explanation for a number less than the theoretically 

 correct number of superimposed age series : it is more difficult to explain the capture 

 of immature whales with a greater number of age series than their physiological con- 

 dition warrants, unless they really are of greater age. 



While therefore the foregoing cannot be advanced as proof of the contention, it does 

 suggest that the apparent disproportion between the catch of sexually mature and im- 



