SEA-FISHERIES LABORATORY. 117 



caught off the south-west coast of Ireland and landed at 

 Fleetwood by a steam trawler. The worm has been 

 recently well figured by T. Scott,* and I have nothing 

 to add to his notes regarding its appearance and 

 occurrence. 



4. Gyrodactylus elegans, Nordmann. 



A number of specimens of a Trematode, certainly a 

 Gyrodactylus, and very probably the above species, were 

 observed on the fins of a small plaice, about 7 cms. 

 in length, living in the aquarium tanks at the Marine 

 Laboratory at Piel. The fish was one of a lot that had 

 been trawled in Ulverston Channel, Morecambe Bay, but 

 though most of those retained in the tank were examined, 

 the Trematode was only seen on one specimen. Both 

 dorsal and ventral fins were infected, but not the tail fin, 

 nor the gills, and no parasites were observed on the 

 general surface of the ho&j. The fish could not be 



Fig. 4. Gyrodactylus elegans. x 125 dia. 

 examined at once, and therefore the fins were cut off and 

 preserved in weak formalin. The state of the parasites 

 was far from satisfactory when they were afterwards 

 examined, and I have some doubt in identifying it as 

 G. elegans, though it seems to be very Dear this species. 

 The average Length and breadth are aboul O'l and 

 0'05 mm. respectively. The large sucker bears (wo long 

 recurved hooks, which are about 0*05 nun. in length; and 

 there are sis or -even pairs of smaller hooks on the 

 margins, lateral and posterior. Most of the specimens 

 contained embryos. 



* Twenty-eighth Annual Eept. Fishy. Bd. for Scotland, pt. 111. 

 I»l. VI II, L891. 



