SEA-FISHERIES LABORATORY. 173 



(C.) From Roosebeck Scar, outside Barrow Channel — 

 " not infected " (Jameson). 



(D.) Roosebeck Scar mussels transplanted to foreshore 

 at Piel two years ago — " all were infested " — " each 

 contained several small pearls " (Jameson). 



Of (A.) I examined a sample of 25 mussels, which 

 contained in all 151 pearls and 11 parasites, but 4 of 

 the specimens had neither pearls nor parasites, and 

 no less than 18 out of 25 had no parasites. I 

 cannot therefore agree that " every specimen is 

 abundantly infected." 



Of (B.) I examined also 25 mussels, which showed in all 

 21 pearls and 22 parasites, 7 had neither pearls nor 

 parasites, and 13 had no parasites. These then 

 showed far fewer pearls than (A), but twice as many 

 parasites, and fewer of them were free from infection. 

 They can scarcely be called " practically without 

 parasites." 



Of (C.) I examined 28 mussels, which contained 73 

 pearls and 37 parasites, 4 had neither pearls nor 

 parasites, and only 9 (out of 28) had no parasites. 

 These then are evidently just as much infected as 

 the mussels on the Piel foreshore. (A.) 



Of (D.) I examined 24 mussels and they contained 65 



pearls and 26 parasites, 3 had neither pearls nor 



parasites, and 12 out of 24 had no parasites. So in 



place of these transplanted " Roosebecks " having 



become more infected on the Piel shore, they on the 



whole showed rather less infection than the mussels 



taken direct from the parent bed. 



Finally, I examined a sample of 25 cockles from Piel, 



and found in them eight pearls, but no parasites at all of 



the right kind. This does not support the view that the 



