44 American Fisheries Society 



development upon the sheepshead as expected and imme- 

 diate shedding by the black bass, the black crappie, and 

 the bluegill sunfish. Mr. Surber (1913)* reported the 

 host as unknown. Two other species of Plagiola have 

 been reported on this fish and one of them, P. donaci- 

 formis, seems to be very common here at Fairport on 

 the sheepshead, so that we apparently have three species 

 of one genus confined chiefly to one host, together with 

 other species of paper shell mussels which are at present 

 considered of little value. 



The three fish, the gar, the shovel-nosed sturgeon, and 

 the sheepshead or grunter, which we find to be the car- 

 riers of these mussels have held economically quite dif- 

 ferent positions. The sheepshead and shovel-nose are 

 now esteemed food fishes, although it is not many years 

 ago that the latter was considered worthless. The gar 

 at present is well known, and as I intimated above 

 is considered a nuisance and, worse than that, a positive 

 menace to the welfare of other fishes. The discovery 

 then that it is practically the sole host for one of the 

 most desired of shells is perhaps not agreeable. As a 

 rule, however, we have to take nature as we find her, and 

 for those who expect always to find a raison d'etre for 

 each creature, this nursing of the yellow sand shell by 

 the voracious gar will satisfy the belief that things are 

 as they should be. 



These results open up interesting problems as to de- 

 tails in the ecological relations of the associated species 

 and the nature of the specific reactions which control 

 them. These are applicable to all cases of specific para- 

 sitism and have been solved for some. It is of practical 

 importance to those interested in mussel propagation that 

 at least an answer be found for some of the questions 

 of this nature raised here. 



*Surbur, T., 1913: Notes on the Hosts of Fresh Water Mussels. Bui. 

 Bureau of Fisheries. 



