40 G. E. H. BARRETT-HAMILTON [july 



accountable for, and hence only 17 per cent away. The chief change 

 was due to the fact that fewer cows seemed to be lying on the beach 

 than before, but these lay on the rocks or reef or in the sea in the 

 immediate vicinity of the rookery. 



There are, I think, only two deductions which can fairly be made 

 from the above figures, and these are either — 



1. All the females had pups, and in that case there was no day 

 up to the 1st August on which a percentage of more than seventeen 

 left the rookery for any length of time, or — 



2. If the percentage of females at all times absent from the rookery 

 is to be here applied as on the Pribilofs, the obvious deduction is that 

 there was an unknown and somewhat considerable percentage of the 

 females which were without pups, and which, hanging about the neigh- 

 bourhood of the rookery, made up the numbers of seals which were 

 daily to be seen. 



Movements of the Pwps. 



The movements of the pups seemed to coincide with the rise and 

 fall of the tide. At low tide they followed their mothers out on 

 the reef, and slept with them on the outlying rocks. The rising tide, 

 however, caused the swell to break over these rocks, and even to send 

 a small breaker right across the reef. The pups always retired to 

 the shore before this breaker, and on the day of our most successful 

 count (29th July, at 6.15 p.m.), out of a total of 529 pups counted 

 by myself, and 527 by Dr. Stejneger, only three were in the water or 

 off the beach. 



On these well-protected rookeries the pups learn to swim rapidly, 

 and although up to the 30 th of July there were no pups at the south 

 rookery who dared face the surf or the waters of the deep sea, there 

 were on that date 370 out of 530 who were capable of swimming 

 about in the shallow water on the reef. There can be little doubt 

 that they here learn to swim by following their mothers out on to the 

 reef, where the rising tide cuts them off, and they are then forced to 

 use their nippers. One little pup which Dr. Stejneger and I watched 

 on the 29th of July had evidently never tried to swim before. It 

 was cut off by the advancing tide while sitting with its mother on a 

 small rock on the reef. As the tide advanced, the pup tried to balance 

 itself on the top of the rock in a seemingly most uncomfortable posi- 

 tion. Presently the cow moved off, and the pup had to follow her 

 into the shallow water, but it was only after some time, and when it 

 was teased by some other pups, that it dared to put its head under 

 the water, and when it did do so it swam excellently. 



On the 30th July a good many pups at the South rookery were still 

 afraid to go into the shallow water, as I saw when I went down 

 amongst them to remove some dead carcases. They must, however, 

 have progressed pretty rapidly in their swimming- lessons ; for, whereas 



