38 G. £. H. BARRETT-HAMILTON [JULY 
but it was difficult to tell exactly, as the contents of the stomachs 
were somewhat decomposed. This observation is of interest in view of 
the statement by Dr. Stejneger (Report p. 69) that he “was informed 
that once on the South rookery a flock of bachelors was so full of 
octopods that they vomited up quantities of these mollusks while 
being driven.” 
On the whole, however, the stomachs are almost empty, containing 
only a little mucus, bile, a pebble or two, some parasitic worms, and, 
perhaps, some fish bones or beaks of squid. These, the remnants 
of the last meal devoured by the animal, are usually regurgitated on 
the rookery grounds, whence a collection of fish bones may be made 
such as will give a clue to the food of the seals, and in which the 
Pacific pollak was found, as on the Pribilof Islands, to play an im- 
portant part. At sea the contents of the stomachs are very different, 
and Mr. Lucas and I found many full ones (12 out of 26 examined) 
when cruising on the U.S. Revenue cutter “Rush” among the 
pelagic sealers in Bering’s Sea. On this occasion I thought I noticed 
a connection between the full stomachs and the empty milk-glands, 
and empty stomachs (or those containing only a few fish bones) and 
full milk-glands, seeming to show that the mother-seals go to the sea 
with their milk-glands quite empty and then eat largely and sleep until 
their milk-glands are again full, which occurs about the time that 
their meal has been digested. 
Not only do the seals cast up fish bones on the rookeries but deposit 
there parasitic worms and excrement and urine in great quantities, so 
that the rookeries are by no means pleasant places to tramp over: the 
rocks are often slippery and the odour always characteristic. Add to 
which the fact that on the Commander Islands at least the seals are 
infested by great quantities of a small dark fly, and it may well be 
imagined that it is often pleasanter to look at the seals from a distance 
than to walk among them. 
I think it is to the urine that must be attributed the growth of 
yellow grass (Poa sp. ?) which first appears on ground formerly occupied 
by seals but deserted by them. Such grass had to me very much the 
appearance of that which springs up on the bare places where rabbits 
have been feeding on a lawn. 
Summary of Statistical Results. 
My statistical results show the following :—Assuming that the 
total number of pups on the South rookery from the 24th to 30th July 
was 550, that there was no appreciable increase in their number in 
that time, and that there were no pupless females on the rookery, 
then there were on the beach during a series of twenty observations a 
number of females which varied from less than 1 to over 59 per cent 
of the whole, and which was, within those limits, exceedingly variable, 
