48 



THE DISTRIBUTION OF PARASITE- 

 INFECTED FISH. 



By H. CHA8. WILLIAMSON, M.A., D.Sc. 



{Fisher y Board for Scotland, Aberdeen.) 



Among the fish landed at Aberdeen there are two notable classes that 

 are infected by parasites, and it appears that they can be traced to two 

 definite areas of the sea. I refer to what are known as "spotted had- 

 docks," and "worm-infested codlings." 



The spotted haddock is a fish of plump condition, in the muscles of 



Fig. 1. 



which are distributed the cysts of a peculiar parasite which has been 

 named Dokus adiis Fig. I , jxi. A somewhat similar organism was found 

 by Hofer in diseased trout. The infected trout became lethargic and 

 swam about intermittently in a staggering fashion. Hofer regarded the 

 parasite as a spoiozoan. Pleyn and Mulsow however found a fungoid-like 

 budding in cultures of the cysts, and they came to the conclusion that 

 it was a fungus. They named it Ichthyophonus hoferi. The parasite was 



