CONTRIBUTIONS FROM THE BIOLf^ICAL LABORATORY OF THE BUREAU OF FISHERIES 



AT WOODS HOLE, MASS. 



'HE FISH PARASITES OF THE GENUS ARGULUS FOUND IN THE WOODS 



HOLE REGION. 



By CHARLES B. WILSON, 

 Department of Biology, State Normal School, West field, Mass. 



The summer of 1871 witnessed the first effort on the part of the United Mates 

 Fish Commission to obtain a knowledge of the invertebrate fauna of Vineyard Sound 

 and adjacent waters, and thus of the parasites that infest the fish of that region. 

 The results were embodied in an admirable monograph by Verrill and Smith, which 

 has become the foundation of all subsequent work. In it were descriptions of three 

 species oiArgvlus, all of which were new to science, but as they were captured while 

 swimming freely at or near the surface, not even one of their hosts could be deter- 

 mined. Two other species were mentioned as likely to occur in the vicinity, but one 

 of them, alotsse, had never been seen since 1817, when it was found by Harris in 

 Boston Harbor and very poorly described by Gould in his Invertebrata of Massa- 

 chusetts, while the other species, catostomi, had been found only upon the suckers 

 in Mill River, near New Haven, Conn. 



Since this first effort in 1871, the work has been carried forward steadily by 

 members of the Fish Commission, and large collections have been made, showing 

 the hosts for the various specimens taken. Especially should be mentioned the 

 efforts of Mr. Vinal N. Edwards, whose extensive study of the fishes themselves has 

 brought him frequently in contact with the parasites which infest them. Fully 

 three-fourths of the entire collection of Argvli bear his signature, so that the deter- 

 mination of hosts and breeding seasons is almost wholly a result of his labors. 



The material thus accumulated eventually found its way into the United States 

 National Museum, and about a year and a half ago the entire museum collection was 

 placed in the author's hands for purposes of study, at which time and since every 

 facility within the command of the Fish Commission has been generously placed at 

 his disposal. This has made it possible to determine with accuracy much that was 

 previously in question with regard to the sexes of the Arguli, their breeding seasons, 

 the place and manner of depositing the eggs, the period of incubation, the main 

 features of development, and many of the habits that result from parasitism. These 

 facts are embodied in a paper already published in the Proceedings of the United 

 States National Museum (Vol. XXV). but as that paper includes all the known species 

 of the Argvlidm, both American and foreign, fresh water and marine, it has been 

 thought advisable to select the forms that are known or are likely to occur in the 



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