THE LEOPARD SEAL HYDRURGA 

 LEPTONYX (DE BLAINVILLE) 



By J. E. Hamilton, m.Sc. 

 (Plates VlI-XIIl; Text-figs. i-6) 



INTRODUCTION 



THE leopard seal {Hydrurga leptonyx) is the second largest of the Phocidae but it 

 has been somewhat neglected by zoologists, owing no doubt to the belief that it is 

 a common species, and a little search of the records of it will show that, although it is 

 very widely distributed in the Antarctic and Subantarctic regions, it is one of the rarer 

 seals. 



I would express my sincere thanks for assistance in this research to the Staff of the 

 British Museum (Natural History), to Dr A. J. E. Cave, Curator of the Physiological 

 Collection in the Royal College of Surgeons who had prepared for me the original of 

 Plate XIII, and particularly to Mr G. C. L. Bertram of the Zoological Laboratories, 

 Cambridge, who generously placed at my disposal the valuable collection of material 

 derived from this species which he collected during the British Graham Land Expedition 

 1935-7. I would also record my gratitude to Mr Charles Robertson, Manager of Port 

 Stephens Station, West Falkland, for assistance in forming my own collection. 



HISTORICAL 



The original description of the leopard seal is that of de Blainville (1820) and it was 

 based on two specimens, one skull in the collection of the College of Surgeons, no. 1901, 

 and a skull with the skin in the collection of M. Hauville at Havre. Barrett-Hamilton 

 has discussed the College of Surgeons' specimen in the ' Southern Cross' reports (1902) 

 and established its identity. South Georgia is therefore the type locality. The skin and 

 skull at Havre passed to the Musee National d'Histoire Naturelle in Paris, and, owing 

 to the great kindness of M. P. Rode, Assistant at the Museum, I am able to state that the 

 skull is there now. It is a young male and somewhat damaged in the basioccipital 

 region. The skin belonging to this skull became very dilapidated and was destroyed in 

 1914. These two specimens are therefore syntypes of the species. 



Weddell (1825) mentions the "sea leopard" as if he were familiar with it, but the 

 earliest description of it in the flesh is that of Ross (1847), who did not name each of the 

 three species of seal which he described although he discriminates between them. Ross 

 writes: "There were three kinds: the largest of them is of great size, measuring in 

 length nearly 12 feet and six in circumference, but varying much in weight according 

 to the condition of the animal ; the heaviest we killed weighed 850 lbs. and yielded 



