SEA-FISHERIES LABORATORY. 113 



SOME PARASITES FOUND ON FISHES IN THE 



IRISH SEA. 



By Andrew Scott. 



No subject offers a more enticing attraction to the 

 Zoological student than the one that deals with those 

 members of the animal kingdom which through some 

 acquired habit have become partly or altogether dependent 

 on other animals for their food. This branch of research 

 has been very prominently brought to the front within 

 the last two years by the further investigations relating 

 to the formation of pearls in the common mussel of our 

 sea shores, by Dr. II . L. Jamieson, and of the extremely 

 valuable oriental pearl from the Ceylon pearl oyster, by 

 Professor Herdman and Mr. James Hornell. 



It has long been known that the completion of the 

 life cycle in some parasites, such as the " liver fluke " in 

 sheep, is wholly dependent on part of the development 

 being carried on in another animal ; and it is becoming 

 more and more evident that the life-cycle of these parasites 

 can only be completed when the creature has successfully 

 passed from one stage to another, and reached its final 

 host where reproduction takes place. 



The difficulties that await the student who contem- 

 plates investigating the life histories of parasites are great, 

 but by no means insurmountable. Extreme care and 

 much patience are necessary, but the work is well worth 

 the labour expended and there is still much to do. 



In the following notes a list of the parasites that have 

 been recorded from the fishes caught in the Irish Sea is 

 given, with remarks on some of the more important points 

 connected with each. It is probably far from exhaustive, 

 but will form' a foundation for future additions. Up to 

 i 



