SPECIES OF WHALEBONE WHALES 203 



two principal objects : first, to collect sufficient material for an adequate description of 

 each species and its range of individual variation, and secondly, to discover whether 

 there exist any subspecies or races which might imply some form of segregation of the 

 stocks of whales. On the first point all that need be said here is that full descriptions of 

 the external characters and their variation (often accompanied by numerous photo- 

 graphs) are to be found among the publications mentioned above; and the measure- 

 ments of bodily proportions at least of Blue and Fin whales, and perhaps also of Hump- 

 back and Sei whales, in the South Atlantic sector of the Southern Ocean, will perhaps 

 be regarded as sufficiently extensive to establish mean values and the approximate range 

 of variation. Some differences in the bodily proportions at different stages of growth 

 have also been demonstrated, the anterior part of the body being relatively larger, and 

 the posterior part relatively smaller, in the full grown than in the young whale. On the 

 second point little more than negative evidence is available, but the question deserves 

 more detailed consideration. 



The specific differences between Blue, Fin and Humpback whales are obvious and 

 clear cut. The distinction between the Sei whale and Bryde's whale is not so evident, 

 but it seems to be accepted that they are distinct species. Members of the Discovery 

 Committee's staff have not had an opportunity of making a proper examination of any 

 example of Bryde's whale ; but although it is in most respects very similar to the Sei 

 whale its coarse baleen is said to be quite different from the fine baleen of the latter 

 species, and certain differences in the skeleton are described by Lonneberg (1931) (see 

 also Andrews, 19160, p. 379, and Olsen, 1913). Bryde's whale is remarkable for its 

 apparently very limited distribution. It has not been identified with certainty except 

 at South African stations, and on one occasion in the West Indies. 



It cannot be said that any subspecies or races have been proved to exist. We have to 

 consider the possibility, first, of some difference between whales of the northern and 

 southern hemispheres ; secondly, of subspecies segregated or tending to segregation in 

 different parts of the southern hemisphere ; and thirdly, of more than one subspecies or 

 race mingling in the same locality. 



Since whalebone whales are relatively plentiful in high latitudes but scarce near the 

 equator, differences might be sought between the northern and southern population. 

 There are not sufficient data for a complete comparison between the whales of the two 

 hemispheres, but the descriptions, for example, of the external characters of Blue, Fin, 

 Humpback and Sei whales, published in the Discovery Reports, tally very closely with 

 True's descriptions (1904) of the same species in the North Atlantic, and it is unlikely 

 that any real difference exists. 



Much the same may be said of whales in different parts of the oceans of the southern 

 hemisphere. A detailed comparison of the measurements and external characters of 

 Blue and Fin whales taken at South Georgia and South Africa has been made by 

 Mackintosh and Wheeler (1929), but no differences could be distinguished. Matthews 

 also (1937, 1938c) finds no differences between Humpback and Sei whales of South 

 Georgia and South Africa. He discusses, however, certain colour varieties of Hump- 



