EXTERNAL CHARACTERS OF WHALES 271 



is no doubt at all that the local whale population is subject to far less fluctuation off 

 the south-west African coast than in the neighbourhood of South Georgia. 



We left the Cape in October 1926, arriving again in South Georgia in November. 

 Work was recommenced on November 15 and continued from then to April 25, 

 1927. This season's catch showed certain points of special interest. A feature of the 

 first part of the 1925-6 season was the great scarcity of whales, especially of Blue 

 whales. The 1926-7 season was characterized by a great abundance of Blue whales 

 which was maintained right on to March, and a scarcity of Fin whales in the earlier 

 part of the season. From the whaling industry's point of view the season was even 

 more successful than the preceding one, for although whales were at no time quite so 

 abundant as in January and February 1926, the supply was plentiful throughout the 

 season. As in the last season the whales caught in November and December were on 

 the average very large. During the second half of the season smaller whales began to 

 appear and the average size became considerably less. A peculiar feature of this 

 season's catch was the appearance towards the end of February of Sei whales. These 

 were the first which had been caught at South Georgia during the whole of our stay, 

 and through March and April they became very plentiful, 63 being examined before 

 the end of the season. 



It should be mentioned that the 1926-7 season was characterized by the phenomenal 

 amount of ice which had drifted as far north as, and even farther than. South Georgia. 

 There is little doubt that this was correlated in some way with the exceptional 

 abundance of Blue whales throughout the season. 



In May 1927 the Marine Biological Station was closed and the staff returned to 

 England. It was reopened early in 1928 and work on the same lines was started again 

 at the whaling station on February 15 by Messrs Fraser and Rayner. 



EXTERNAL CHARACTERS 



Among all the whales examined six distinct species are included, and representatives 

 of each of these have occurred both at South Georgia and at Saldanha Bay. Not many 

 whales have been examined apart from Blue and Fin whales, and the present memoir 

 is really concerned only with the two latter species. The other species will no doubt 

 be dealt with in due course when more material has been collected. 



The following are the names now generally adopted for the six species mentioned 



above : 



Mystacocoeti (Baleen whales) 



Balaenopteridae (Rorquals) 



Blue ... ... ... ... ... ... Balaenoptera musculiis 



Fin ... ... ... ... ... ... B.physaliis 



Sei ... ... ... ... ... ... B. borealis 



Humpback ... ... ... ... ... Megaptera ftodosa 



