TREMATODES OP THE NORTHUMBERLAND COAST 39 



in Cardiuiii edule on the Lancashire coast*, and by Huetf in 

 the same mollusl^ in Normandy, 



Encysted Trematodes are not uncommon in fish. One 

 frequently found off our coast is from the Dab Pleuronectes 

 limanda. This worm is described by Johnstone^ from the 

 West coast of England, and he refers it to Distonmm valde- 

 inflaticm, Stossich. I have found what seems to be the same 

 species in our local Dabs, especially in the younger specimens, 

 as Johnstone describes. They occur beneath the skin of the 

 under side, and also now and then on the gills. I have also 

 found it, but not so frequently, in the Long Rough Dab Hippo- 

 glosstis limandoides, Lemon Dab Pleia-onectes mic7-ocephahis 

 and Witch P. cyiioglossus. My specimens (length when pressed 

 out of cyst 2'g-3 mm.) are larger than Johnstone's (about 

 1*25 mm.), but his are not so far developed as mine. It is 

 possible that they represent different species, but it is more 

 probable that they are the sam^e, for my specimens agree 

 very well with his description so far as it goes ; but few 

 measurements are given, and the number of head spines is 

 not stated. 



The worm (Plate IL, fig. 3, 4, 5, 6) is enclosed in a double 

 sac, the first very thick and tough, and the second transparent 

 and showing the coiled-up worm through its walls. When 

 pressed out of the cyst the worm is seen to have the shape of 

 a very elongated pear, with its body covered with strong 

 spines gradually disappearing towards the posterior end. At 

 the head end they are very conspicuous, and round the anterior 

 sucker there are two rows of very distinct spines. The body 

 spines are slightly curved, but those round the head are 

 straight (see fig. 4) and taper to a point distally. Those of 

 the upper row are shorter than those in the lower (upper spines 

 o"o2 2 mm. long, lower spines 0*026 mm. long.) The number 



* Johnstone, J., "Internal Parasites and Diseased Conditions of Fishes," 

 Lancashire Fisheries Report for 1904, p. 107, PI. V. 



t Huet, " Note sur le Bucephalus haimeanus ," Bull. Soc. Linn. Normandie, 

 s€r. 4, T I.I., fig. 3-4. 



% Johnstone, J., Op. oit., p. 98. 



