American Fisheries Sdcieiy 97 



infection in the intestine as those wliich were taken from salt 

 water at the beginning of migration. I shonld note in ])assing 

 one a])])arent exception to this rnle. The red salmon taken from 

 salt water contain occasionally specimens of a large tapeworm 

 closely related to Hothriotaenia infundihuliformis. This species 

 was not found e^■en in a single case among the specimens taken 

 from fresh water. Summing up then the results of the investi- 

 gations on the Alaska salmon in this particular one may say that 

 intestinal parasites are variable and infrequent at all times. 

 Contrary to the findings of Zschokke for the Rhine salmon the 

 parasites do not disappear from the intestine at any timt' in tlu' 

 migration, with the possible exception that this single large 

 cestode seems to be wanting under conditions of fresh water 

 existence. 



Such parasites as exist in the pyloric region are apparently 

 not aft'ected l)y the migration altliough the large cestode previous- 

 ly referred to was not found in those hosts which had attained 

 the fresh water lakes in the vicinity of the spawning grounds. 

 Since, however, this species is not frequent in any series of speci- 

 mens representing this liost. its absence at the end of the mi- 

 gratory period may l)e entirely without significance. Parasites 

 of the stomach and oesophagus are as varied in species and near- 

 ly as abundant in numbers at the close of the migratory period 

 as tliey were at its outset. Furthermore, I am unable to find 

 that these organs shelter during the fresh water existence any 

 of those species which at an earlier time inbal)it the other poste- 

 rior ])ortions of the alimentary canal. Consequently so far as 

 the Pacific salmon is concerned its migration does not affect 

 appreciably the amount or variety of its parasitic fauna. The 

 parasites of the l)ody cavity include an interesting and abvnidant 

 form which is not known to occur elsewhere. This seems to be 

 as numerous and as active in tlie fish on entering the spawning- 

 grounds as in the fish from salt water. Xumerically it consti- 

 tutes one of the most imjjortant elenu'Uts in the parasitic fauna 

 in the Alaska salmon and has no parallel in the forms hitherto 

 re]iorted from the European salmon. 



As in the case of the Khine salmon, so the individuals of the 

 Pacific species are reported not to take food after they lea\e the 

 salt water. In my examinations I have not found food mate- 



