108 U. S. BUEEAU OF FISHERIES. 



the erroneous term " rubbed spots." These are usually on portions of 

 the anatomy which could not be " rubbed " under any circumstances. 

 The number of cases of this disease gradually decreased to a mini- 

 mum by 1917, which remained constant through 1920. 



Ectoparasites of the fur seal are very rare, although the enormous 

 amount of scratching which is visible in any " pod " would leave the 

 casual observer with the impression that the opposite is the truth. 

 In 1899 a louse, Ha^matopinus callorhini Osborn, was described from 

 '' a number of examjjles from the northern fur seal.'' And at the 

 same time a tick, Ixodes orctieus Osborn, was described from a single 

 individual.^ I have made repeated search for these parasites, and 

 several j^ears ago located the louse on pups. Not all are afflicted by 

 an}' means, but occasionally a few specimens can be secured from the 

 eyelids and less often in the fur of the head. No positive information 

 regarding the tick could be secured. A reward of $1 per louse 

 and $5 per tick has been offered to the native workmen who kill 

 and skin some 25,000 animals each year, but there have been only 

 negative results. This leads me to believe that the louse is almost, if 

 not wholly, confined to the pups, and very serious doubt is cast upon 

 the Ixodes arcticus being a parasite of the fur seal at all. 



COWS. 



The number of breeding cows in the herd corresponds to the num- 

 ber of pups, since the one is derived directly from the other. There 

 naturally exists in any year an excess of adult females over young, 

 because there are always a few barren animals. The number, how- 

 ever, has never been considered other than inconsequential and is 

 very properl}^ ignored. The increase or decrease, in fact the exist- 

 ence of the species, is dependent upon the fertile cow ; the others in 

 no loiown way enter into commercial operations of man. 



Formerly it was supposed that the coavs which resorted to the 

 hauling grounds with the bachelors were barren, but this is not the 

 case at all. Thirteen cows which had been accidentally killed on the 

 fields during the past four years have been examined and only one 

 Avas found barren. Several of thom had already given birth to 

 young, but others had not, Avhile the majority were 2-year-olds Avith 

 reproductive organs normal in eA^ery way. 



LOSS or COAVS ON THE ISLANDS. 



The spreading of the bulls incident to the larger aA'-erage harem 

 produced a noticeable decrease in the death rate of coavs on the 

 breeding grounds. Since much of the turmoil and fighting of the 

 past three years Avas thus done away with, such a result Avould be 

 naturally expected. During the counting of 15,965 pups 9 dead 

 coAvs were found. This is a percentage of 0.000563, which applied to 

 the entire herd gives 94 as the total number. Comparable figures for 

 preceding years Avere: 195 in 1919, 213 in 1918, 129 in 1917, and 39 

 in 1916. It shoAvs that in spite of the increase in the herd there 



1 Fur Seal Invostigations, 180G-97, pt. 3, p. 553. 



