332 DISCOVERY REPORTS 



hard to see how the anatomical and physiological work which is really needed could be done in such 

 regions except at prohibitive cost. Such work is only made possible in the Antarctic by taking advantage 

 of the facilities provided by the existing whaling operations. 



With the exception of a few observations made at South African whaling stations (Saldanha 

 Bay 33 i' S., i8° o' E., and Durban 29 52' S., 31 1' E.) some 30 years ago all the material on which 

 this work is based has been collected during a few months of the year in the Antarctic, where the 

 animals migrate to feed on krill. Since the 1950/51 season the pelagic whaling operations for fin 

 whales in the Antarctic have been confined to January, February, and the first part of March. As the 

 main part of the pairing season is from May to July, elucidation of events at this, the most important 

 stage in the annual cycle, could hardly be more difficult. Even the observations from South African 

 land stations are not truly representative of the breeding population, because they are situated near 

 migration routes at positions probably well south of the breeding grounds. 



It is therefore necessary to make inferences from the condition of animals killed in the Antarctic 

 as to the events in the breeding season some six months previously; a procedure which is only 

 justified by necessity. One species of baleen whale, the humpback whale, Megaptera novaeangliae 

 (Borowski) has recently been studied on or near the breeding grounds (which in this species are in 

 inshore waters) and is described in a series of important papers by Chittleborough (1955a, 19556, 

 1958). We may, with certain reservations, draw on this work for comparison. 



Part of the original work described in the present paper has already been presented in two short 

 preliminary papers (Laws, 19580, 19596). 



Acknowledgements 



This paper could not have been written had it not been for the strenuous efforts of the biologists who 

 collected or examined material over a long series of years, first for the ' Discovery ' Committee and, 

 from 1949, for the National Institute of Oceanography. In particular I wish to thank Dr H. E. 

 Bargmann, Dr M. Begg, Dr M. R. Clarke, Dr R. H. Clarke, Mr P. R. Crimp, Mr J. D. Currey, 

 Mr A. E. Fisher, Dr F. C. Fraser, Dr J. E. Hamilton, Dr K. A. Kermack, Dr N. A. Mackintosh, 

 C.B.E., Dr L. H. Matthews, F.R.S., Dr F. D. Ommanney, Dr D. A. Parry, Mr D. F. S. Raitt, 

 Dr G. W. Rayner, Mr A. Saunders, Mr J. H. Smoughton, Mr H. W. Symons, Mr R. D. Weston, 

 Dr J. F. G. Wheeler, and Mr G. R. Williamson. 



My own introduction to whale biology on board F/F ' Balaena ' in 1953/54 owes much to the facilities 

 provided by Hector Whaling Ltd. through Capt. C. P. Virik, and to the co-operation of Cdr H. E. 

 Buckle, A.M., C.B.E., Senior Whaling Inspector, Mr C. E. Ash and Mr H. W. Symons, Chemists, 

 Mr Harry Weeks and many others. I would also like to thank Gunner Ragnar Hem for hospitality 

 enjoyed during a short voyage on board the whale catcher, ' Setter IX'. 



A number of British and Norwegian Whaling Companies have generously co-operated in these 

 studies by providing facilities for biological work on factory ships, or by collecting whale ovaries for 

 subsequent examination in the U.K. (The latter scheme was initiated by Mr A. H. Laurie in 1934.) 

 These are Hector Whaling Ltd., Chr. Salvesen and Co., Johan Rassmussen and Co., A/S Melsom 

 and Melsom, A/S Svend Foyn Bruun, and A/S Thor Dahl. It gives me pleasure to acknowledge the 

 help of the whaling inspectors in the factory ships ' Balaena ', ' Southern Harvester ' and ' Southern 

 Venturer'. The Ministry of Agriculture, Fisheries and Food has been most co-operative. To all these 

 individuals and organisations I am indebted. 



As regards the examination of the material I am particularly grateful to Mr A. E. Fisher who has 

 made most of the histological preparations and, with Mr J. H. Smoughton (to whom I am also 

 indebted) has undertaken nearly all the routine examinations of ovaries since 1955. Dr R. H. Clarke 



