6 DISCOVERY REPORTS 



Wheeler's findings with Fin whales, I have preferred to approach the problem by other 

 methods, since it may be that conditions in Blue whales are such as to prevent the 

 occurrence of peaks. (See p. 259.) 



physical maturity. The presence or absence of ankylosis of the vertebrae was 

 examined in the same 180 whales whose ovaries had been examined. Wheeler (1930, 

 pp. 408-9) showed that with the onset of physical maturity in many species of whales 

 ankylosis of the centrum and epiphysis of the vertebrae takes place simultaneously but 



:-s, 



20 



< 



UJ 



h- 



_l 



< 15- 



a 



2 

 3 







• VERTEBRAE FULLY ANKYLD5ED 



O VERTEBRAE NOT FULLY ANKYLOSED 



000 

 000 000 



00 

 00 



23 metres 24 25 26 27 26 29 3 



1 1 1 1 1 1 i 1 1 1 1 1 1 1 1 ' 1 1 1 I ' ' ' 



80 feet 65 90 95 



LENGTH OF WHALE 



Fig. 5. Lengths of whales and number of corpora lutea. 



at different rates from both ends of the column and is completed in the anterior thoracic 

 vertebrae. It was evident therefore that the criterion of complete maturity lay in 

 ankylosis of the anterior thoracics, which I accordingly examined first. Frequently it 

 was impossible in the heat of work on deck to examine other parts of the column after 

 testing the thoracics, so that very often it was not feasible to make a diagnosis of partial 

 ankylosis if complete fusion was absent. The crucial vertebrae, however, were always 

 inspected. It is therefore possible to correlate the presence or absence of physical 

 maturity and the numbers of corpora lutea in the ovaries with a view to correlating 

 ultimately physical maturity with age. 



