THE AGES OF WHALES 447 



old and that one measuring 23 or 24 m. is unlikely to be less than three or four years 

 old. But one cannot go further than this. 



The old scars left on the whale's skin by the wounds contracted in temperate or sub- 

 tropical waters seem to be cumulative, for they are generally more numerous on large 

 than on small whales, but they are of little value except that they may help to show 

 whether a whale is comparatively old or comparatively young. It would be practically 

 impossible to count the scars and such a figure would in any case convey very little 

 information. 



The condition of the vertebral epiphyses and the numbers of corpora lutea are worth 

 considering in more detail. The former gives an indication of full maturity (and not 

 merely of sexual maturity) and the latter, although it does not take us far, and applies 

 only to females, is in some ways the most important clue to the age of a whale which 

 has so far appeared. 



The ankylosis of the epiphyses with the centra throughout the vertebral column can 

 be taken as marking the attainment of full maturity in the animal and cessation of growth 

 in length. Owen (1853), who found that the skeletons of such whales as were available 

 for study possessed unfused epiphyses, suggested that no fusion ever took place and 

 that the immature condition persisted to give greater flexibility to the body and tail, 

 but Flower (1864) showed that when full maturity was reached fusion took place in 

 whales as in other mammals. He further showed that the fusion first took place in 

 the cervical and caudal regions and proceeded from each end to the middle of the 

 column. 



The examination of the vertebrae at whaling stations would be much more profitable 

 than it is were it not for the practical difficulties involved. At South Georgia the cutting 

 up of the carcasses is accomplished with considerable speed, and as the operation of 

 exposing the epiphyses is a comparatively laborious process it is impossible to carry it 

 out systematically. At Saldanha Bay some opportunities for this work occurred and 

 a number of observations were made upon whales whose length suggested that they 

 might be approaching or past full physical maturity. The method of examination con- 

 sisted essentially in cutting away the periosteum between the vertebrae and exposing 

 the edge of one of them. The state of fusion of the epiphysis with its centrum could 

 then be noted. At the whaling station at Saldanha Bay the vertebral column was usually 

 hauled on to the " bone platform " ventral side uppermost. This permitted the counting 

 of the vertebrae from the first ventral chevron and facilitated the cutting away of the 

 periosteum without assistance from station hands and machinery. As many vertebrae 

 as time permitted were examined, but not more than three could be done at any time 

 before the column was cut up. 



The observations made were as follows : 



