6o Roosevelt Wild Life Bulletin 



Occasionally, however, as a,lready stated, they may infect the gills of 

 a fish in large enough numbers to injure the animal. Not long ago 

 such a species of fluke was discovered on the gills of the rainbow 

 trout in the State Fish Hatchery at Cold Spring Harbor, Long 

 Island. Practically all the trout a year or more old were infected, 

 in many instances in such large numbers that the gills were shrivelled 

 and functionless. 



The larval stage of the Trematodes of fish and other aquatic 

 vertebrates is passed very generally in snails, but also, in the case 

 of certain species, in small fish, in crustaceans, and in other small 

 animals that are the natural prey of the host of the adult worms. It 

 is thus necessary in endeavoring to elucidate the life history of these 

 worms to investigate these animals, especially the fresh-water snails. 

 The study of larval Trematodes has been neglected in this country 

 and observations made on their structure, habits of life, and their 

 relation to their hosts, such as can be made with great advantage at 

 Oneida Lake, will be of great value. 



None of the worms that parasitize fishes and other aquatic verte- 

 brates will live in the human body, with a single exception, which is, 

 however, of such rare occurence in America as to be practically 

 negligible. There need be no alarm, consequently, about the pos- 

 sibility of an infection of parasitic worms as the result of eating 

 the flesh of any fishes, frogs, wild ducks or other similar animals. 

 The exception just mentioned is the broad tapeworm Diphyllohoth- 

 rium latum, which in its adult stage is a common human parasite 

 among the Scandinavian peoples and other fish-eating populations 

 of Europe, and in its larval stage lives in many species of food 

 fishes. 



TABULATED RESULTS 



The following tables show the names of the species of fish, birds, 

 reptiles, amphibians and mollusks that have been examined in the 

 course of this study, the number of individuals of each species 

 examined, and the number of parasites obtained from each species. 

 Where the parasites were found in large numbers in an organ the 

 number given in the table is usually an estimate, as it was often 

 impossible to count them. This was especially true in the case of the 

 Trematode and tapeworm cysts imbedded in the liver and the fat of 

 the mesenteries of certain fish, such as the common bullhead, the 

 bluegill, and the sunfish. In the case of the eels mentioned, but two 

 complete fish were examined. Only the viscera of the others were 

 examined, obtained from a fish dealer. The lists are not complete, 

 as they record the results of but four weeks' work, and will be added 

 to by future collections. They do, however, indicate the distribution 

 of vermian parasites in Oneida Lake animals. 



The animals were collected at or near the town of Brewerton at 

 the western end of the lake, both in the lake itself and in the Oneida 

 River, which is the outlet of the lake. A laboratory equipped with 

 the necessary apparatus and instruments from the zoological labora- 

 tory of the College of Forestry was established at this place. The 

 fish and other vertebrates examined were identified by Frank C. 

 Baker and T. L. Hankinson ; the mollusks by Frank C. Baker, 



