2 5 8 



DISCOVERY REPORTS 



A' is obtained by eliminating from the material all ovaries which came from whales 

 78-81 ft. long, and which contained more than four corpora lutea. It will be recalled 

 that the data were originally trimmed in the light of personal experience to exclude all 

 whales purporting to be 78-81 ft. long and showing more than seven corpora lutea. It 

 may be that an allowance of up to seven corpora lutea in the first breeding season was on 

 the generous side, and that the whale which I found in 1932-3 with seven corpora lutea 

 (length 81 ft.) was really an exceptional whale.) Point C at twelve corpora lutea might 

 well be represented at C" a year later with thirteen to fourteen corpora lutea. Possibly 

 owing to small numbers there are unexplained features in the rest of the curve. D and E 

 seem to have stood still at D', E', but F might be reflected in F. The vertical interval 

 between the related points would of course bear some relation to the mortality in one year. 



1932-33 [180 WHALES] 

 1934-35 [307 WHALES] 



10 15 20 25 



NUMBER OF CORPORA LUTEA 



35 



Fig. 11. Smoothed corpora lutea frequencies, Kerguelen Area, 1932-3 and 1934-5. 



There is thus some indication that the increment of corpora lutea in one year is 

 slightly over one, but probably not as much as one and a half. The progression seems to 

 apply to all ages of adults after the first sexual season. If it did not there would be a 

 piling up of frequencies at the number of corpora lutea at which sexual activity ceased. 



One set of figures is available for considering the effect of a two-year interval. The 

 small collection which I made in 1932-3 (180 ovaries) in the Kerguelen Area yields the 

 smoothed frequency curve shown in Fig. 1 1 . For comparison is shown also the smoothed 

 frequencies for the same area from the data collected in 1934-5 (307 specimens). The 

 pronounced maximum in 1932-3 comes actually at six corpora lutea, but from considera- 

 tion of the neighbouring frequencies the maximum may be set somewhere between five 

 and six ; the sample is too small for absolute accuracy. Two years later the maximum has 

 moved to between seven and eight. Here again at the risk of hair-splitting, one may say 

 that the maximum is nearer eight than seven. The movement of the peak can be said to 

 be slightly over two, so that whales in this area, so far as can be determined from the 

 small samples available, appear to have added slightly more than two corpora lutea in two 



