40 G. E. H. BARRETT-HAMILTON [sULY 
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 Ist 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 Pups. 
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 Pm.), 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 30th 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 flippers. 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 
