38 G. E. 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 (Eeport 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. Ee venue 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 530, 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, 



