98 American Fisheries Society 



that of other species that have been investigated. The 

 shortest periods observed are seven days for a summer- 

 breeder and 10 days for a winter-breeder, the young 

 juveniles being recovered in each case. 



In four shipments of gills from the mooneyes, no infec- 

 tions were found. It was hoped that this abundant and 

 more easily handled fish would prove favorable, but like 

 other species tested with one exception, the glochidia 

 were dropped under 3 days. The other fish that have 

 been tested are, the Sand Sturgeon, S. platorhynchus; 

 Dogfish, A. calva; Spotted cat, /. punctatus; Bullhead, 

 A. nebulosus and A. melas; Yellow cat, L. olivaris; White 

 Crappie, P. annularis; Black Crappie, P. sparoides; 

 Blue Spotted Sunfish, L. cyanellus; Bluegill, L. pallidus; 

 Large Mouthed Black Bass, M. salmoides; Yellow Perch, 

 P. flavescens; Sheepshead, A. grunniens. The exception 

 referred to was the Gizzard Shad, Dorosoma cepedianum, 

 Le Sueur, which gave some indications of being favor- 

 able. The results being inconclusive, however, demand 

 further trial. But even should it be found to carry the 

 mussel, the protection afforded by the very fine gill- 

 rakers render infection impracticable by the ordinary 

 method. 



Summary of Results and Discussion. 



The results substantiate the findings in natural infec- 

 tions, viz. that the herring is a carrier of the nigger-head 

 mussel. 



The Mooneye, Hiodon tergisus Le Sueur, gave nega- 

 tive results as reported for a considerable number of 

 other species when tested with the glochidia of the nig- 

 gerhead mussel. 



The possibility of artificially infecting the herring was 

 demonstrated, as well as a method for holding it in cap- 

 tivity. 



The parasitic period of Quadrula ebenus, under the 

 conditions prevailing at the time of the experiment, was 

 shown to be more than ten days, but the amount of de- 



