SEA-FISHERIES LABORATORY. 209 



plaice to the effects of this fungus, but later cases of 



epidemic disease occurred at Port Erin, and the fish 



that died had all the appearance of those studied by me 



in 1905. An epidemic of this kind was studied by 



E-iddell and Alexander in 1911.* Extensive ulceration 



of the fish was found, and an invasion of the body by 



certain bacteria. There were, however, no traces of a 



fungus in any of the internal organs. It is therefore 



likely that the fungus invasion and the ulcerative 



condition of the fishes studied by me were concomitant 



conditions ; as in the case of the Saprolegnia disease 



among salmon. The ulceration and consequent 



weakening of the fish would predispose it to infection 



by the fungus, spores of which were no doubt widely 



distributed. In the case of the mackerel described here, 



there are, however, no external lesions, so that fungal 



invasion may therefore occur apart altogether from any 



wound of the outer surfaces of the fish's body. 



Fibromatous Tumour from a Halibut (Hippoglossus vulgaris). 



In July last, Mr. T. R. Bailey, Port Sanitary 



Inspector at Fleetwood, sent me part of a tumour taken 



from the body cavity of a halibut landed by a steam 



trawler. The fish was about 4 feet 6 inches in length 



and was in fair condition, apparently quite unaffected 



by the presence of the tumour. The piece of the latter 



sent weighed about 1,250 grams, and was rather less 



than half of the entire growth. It was evidently a soft 



fibroma, and had developed from the peritoneum covering 



the viscera of the fish, where, precisely, is not certain 



from the appearance of the structure. It was fairly 



soft, easily torn, clean and compact on its outer surface, 



which was lobulated, the diameters of the individual 



* "Note on an ulcerative disease of the Plaice." Ann. Bept. 

 Lancashire Sea-Fisheries Laboratory for 1911, pp. 85-91, Pis. I. & II. 



O 



