1164 



BULLETIN OF THE BUREAU OF FISHERIES. 



and it is somewhat difficult to draw a precise comparison with the data for the 

 latter regions. First may be placed such records as concern streams directly 

 connected with the North Sea, and hence with the body of water from which 

 the Rhine salmon come. 



Concerning the parasites of salmon in the Tay, Mcintosh (1863) has recorded 

 certain data. More than 100 fish were examined, few were entirely free from 

 parasites, many were richly infested. The parasitic species were both fre- 

 quent and abundant, although only 10 species are definitely recorded, as against 

 14 in the Baltic and 20 in the Rhine salmon. The species from Tay salmon 

 Mcintosh lists as follows : 



Ascaris (Agamonema) capsularia Diesing. 

 Echinorhynchus proteus Westrumb. 

 Echinorhynchus pachysomus Creplin. 

 Distomum varicum Creplin. 

 Distomum tereticolle Rudolphi. 

 Distomum sp. 



Bothriocephalus infundibuliformis Rudolphi. 

 Tetrabothrium minimum von Linstow. 

 Tetrarhynchus macrobothrius von Siebold. 

 Tetrarhynchus sp. 



The examination of this list shows clearly that the Scotch salmon combines 

 elements from the parasitic fauna of both its relatives, the Rhine salmon and 

 the Baltic salmon. The strong and continued infestation of the intestine below 

 the pylorus goes to establish the fact that the taking of food is continuous. 



No seasonal distribution of parasites could be noted, but the character of 

 the parasitic species was striking. One pure marine species and two almost 

 equally such, together with five characteristic salmonid parasites, show that the 

 major portion of the parasitic fauna is of marine origin. On the other hand, the 

 intestinal parasites were in large part not marine, but limnetic forms or such as 

 are typical in the salmon. As in the Rhine salmon, so also in the Tay, the marine 

 alimentary parasites are gradually lost without being renewed. They are replaced 

 by such as are of evident limnetic character. Hence the conclusion of Mcin- 

 tosh, based on other evidence also, that the Tay salmon does from time to time 

 take nourishment during its stay in fresh water. A comparison of the parasitic 

 fauna of the three salmons gives, according to Zschokke, the following: 



