76 THE PUR SEALS OF THE PEIBILOF ISLANDS. 



the presence of 635 dead on the one and 1,895 on the other, the level sands of Tolstoi 

 being so strewn with bodies as to suggest a battle field after some hotly contested 

 encounter. See Plate XVII. 



The first very evident fact regarding these dead seals was that the vast majority 

 had been a long time dead, some bodies being swollen and distorted, while the flat- 

 tened, hairless condition of others bore testimony not only to the length of time they 

 had been dead, but to their ruthless trampling beneath scores of shuflfling feet. The 

 early date at which many had died was apparent from the numerous instances in 

 which the umbilical cord was still attached to the body, indicating that the little fel- 

 lows had been killed shortly after birth. The length of time that most had been dead 

 was also well shown by the small proportion available for dissection, for, although 

 every effort was made to obtain as large a number as possible, only 103 were obtained 

 on St. Paul in 1896 between August 6 and August 14, and not one of the 735 pups 

 found dead on St. George was dissectible. 



The next very obvious fact was the large number of bodies lying on level, unob- 

 structed patches of ground where, earlier in the season, the breeding seals had been 

 densely massed, and where, as on Tolstoi, Zapadni, and Polovina, there had been 

 much fighting and confusion. Eocky slopes were comparatively free from dead, and 

 there were fewer still on rookeries composed of water- worn bowlders, as are the Lagoon 

 and Zapadni Eeef. 



The direct relations between the character of the ground, the numbers of breed- 

 ing seals, and the number of dead pups, and the fact that many of the more recently 

 dead were bruised,' seemed to point to the trampling of the larger seals, and espucially 

 of the bulls, as the cause of death. This inference was apparently sustained by the 

 invariable verification of predictions, based on a careful study of the first rookery vis- 

 ited, as to the rookeries or parts of rookeries on which dead pups would be found most 

 numerous, and in the preliminary report of 1896 it was stated that deaths among 

 young pups were almost solely due to trampling. 



However, in dissecting the pup penned up and allowed to starve, a few small 

 nematodes were found in the small intestine, and as this young seal was nursing, and 

 in consequence they could not have been obtained from fish, the parasites were pre- 

 served, and, with other specimens, submitted to Dr. C. W. Stiles for examination. 

 Dr. Stiles indentified the nematodes as belonging to the genus Uncinaria, and in his 

 report stated that under proper conditions this worm might play an important rdle in 

 the mortality of the pups.^ 



Being aware of the possible presence of a dangerous parasite, on the visit of the 

 commission in 1897 a careful search was made for this nematode, with the result 

 that it was found to be present in great abundance, completely realizing the state- 



' It may be said that the number of pups bearing bruises and obviously trampled on was greater 

 in 1896 than in 1897, for the reason that there were more seals m the former year and they were more 

 densely massed, so that there was a greater chance for a pup to be stepped on. 



2 In Professor Thompson's report on his mission to Bering Sea in 1897, page 8, he says: "During 

 last winter Dr. Stiles, a well-known American helminthologist, reasoning from the very high mortality 

 of the pups on sandy as compared with that on the rocky areas, suggested to the American commis- 

 sioners that a cause of the mortality might be found in a parasitic worm of the genus Uncinaria 

 (Doehmius), which passes a portion of its life history in sand. * * » " xhis was written before the 

 conference of November, 1897, and before hearing the report of the writer on Uncinaria, and is wholly 

 erroneous, the facts being as given above. 



