SEA-FISHERIES LABORATORY. 143 



NOTE ON A REMARKABLE PARASITE OF 

 PLAICE AND FLOUNDERS. 



By H. M. Woodcock, B.Sc. (Lond.). 



In corresponding with Mr. Johnstone about the 

 Glue/ ea-iniection of the plaice, above described, he in- 

 formed me of what seemed to be another Myxosporidian 

 infection of a flounder (Pleuronectes flesus), instances of 

 which, he says, are not nnfreqnently met with. In 

 looking up the literature on parasites of flat-fish, I came 

 across the papers by Lowe (2), Mcintosh (3), and Sande- 

 man (-i), which would appear to refer to the same thing. 

 As Sandeman practically gives the substance of 

 Mcintosh's two papers, accompanied by figures, a brief 

 abstract of his note " On the Multiple Tumours in Plaice 

 and Flounders " will suffice. 



The tumours were prevalent more or less all the year 

 round, occurring principally from May to November, and 

 giving the fish an emaciated appearance. The situation 

 of these cyst-like swellings was in the skin and dermal 

 tissue of the fins, the operculum, and the tail, usually pro- 

 jecting externally. Sandeman does not say whether the 

 gut or other internal organs were affected. The little 

 swellings are described as pearly-white spheres, not firmly 

 attached, but loose in the connective-tissue, covered over 

 by the pigmented epithelium, and exuding on pressure a 

 creamy-white, structureless substance. The larger masses 

 form tumours up to nearly an inch in size, composed of 

 many spheres from 1 to 1\ mm. in diameter, often, how- 

 ever cuboidal or polygonal owing to mutual pressure, and 

 each limited by a distinct membrane. The author remarks 

 on their great resemblance to a mass of eggs, but admits 



