1 1 84 BULLETIN OF THE BUREAU OF FISHERIES. 



and incline to the belief that the form which he observed may have been the 

 species under discussion. 



The European species, . I zygfia tereticollis, has been reported irom Esox Iticius, 

 Lucioperca sandra, Lota vulgaris, Trutta variabilis, Salino truita, Salmo jario, 

 Salmo hucho, Salmo alpinus, and Salmo salar. All of these save Salmo salar are 

 fresh-water fish, and the parasite may be regarded as a characteristic of fresh- 

 water species. The American species, Azygia sebago, I found in Salmo sebago, 

 Esox reticulatus, Osmerus mordax, Anguilla chrysypa, and Perca flavescens. 

 Stafford recorded what may have been the same from Esox liicius, Lota maculosa, 

 and Ameiurus nigricans. These include strictly fresh-water forms, landlocked 

 species, and one migrator)^ fish, but inasmuch as the records have been taken in 

 fresh water even the last host does not constitute any evidence against the fresh- 

 water habitat of Azygia sebago. Its congener, Azygia tereticollis, found by 

 Mcintosh in the salmon of the Tay, formed part of the evidence that this host 

 feeds during its fresh- water residence. Equally here we may regard A. sebago 

 as a fresh-water element acquired by its host since the latter became landlocked 

 in Lake Sebago. The presence of the parasite in several other characteristic 

 fish of the same water basin is clear evidence of the sources from which it might 

 have come. 



CESTODES. 



Cestodes constituted the most conspicuous element of the parasitic fauna. 

 Every salmon opened contained a mass of large worms in the pyloric region. 

 They lay with the head and anterior portion of the body in a pyloric coecum 

 usually at or near its tip. The worms were large and the body was thrown into 

 loops which occupied the initial coecum and folded through the intestinal canal 

 into other ca-ca, often crowding them full apparently to bursting. Viewed from 

 the body cavity, even before the viscera were opened, one could distinguish the 

 coeca which contained the parasites by their opaque, chalky appearance in distinct 

 contrast with the translucent character of those coeca in which there were no 

 tapeworms. When the intestine was opened it appeared full of the cestodes, 

 which protruded in loops hanging from the coeca into the cavity or crossing into 

 other coeca in a tangled mass, in several cases large enough to distend the wall 

 conspicuously. The anterior coeca were those primarily or chiefly occupied by 

 the worms and although often the entire cavity of the intestinal canal was 

 crowded full of parasites, it was noteworthy that they rarely if ever entered any 

 of the posterior coeca. When few worms were found they lay with the scolices 

 at least in the coeca of the most anterior region. 



The species to which I have referred in the preceding paragraph is the well- 

 known Bothriocephalus infundibuliformis, according to Liihe (1899) more cor- 

 rectly designated Abothrium crassum, which is so common in the Atlantic salmon 



