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A Peculiarly Abnormal Specimen of the Turbot. 



By 

 J. T. Cunningham, M.A., F.Z.S. 



With Plate III. 



The specimen which forms the subject of this note was sent to Dr. 

 Allen by Miss Olivia L. Fox, of Falmouth, at the beginning of Decem- 

 ber, 1906, preserved in formalin. Dr. Allen sent it to me in London, 

 and requested me to study and describe it. The specimen is 4"4 cm. in 

 length, and presents a condition which has never previously been 

 described in any species of flat-fish. I have examined it with great 

 interest, and would express here my thanks to Dr. Allen for sending it 

 to me. 



With respect to the position of the eyes the fish is a reversed speci- 

 men, that is to say, both eyes are on the right side, whereas normally in 

 turbot they are on the left. With respect to colour, on the contrary, 

 the specimen partially resembles a normal turbot : the right side is 

 almost entirely unpigmented, the greater part of the left side is coloured 

 as in a normal specimen. The pigmentation does not extend uniformly 

 over the whole of the left side, but is absent from the head, and from 

 the anterior part of the dorsal region above the head. On these areas 

 there are only a few scattered black chromatophores. On the right or 

 uncoloured side there are also scattered black chromatophores, rather 

 more numerous than on the left side of the head. It is important to 

 note that the head and anterior region of the right side, although not 

 fully pigmented, have more pigment than the rest of that side : between 

 the eyes and around the dorsal eye pigmentation is almost complete. 



The number of dorsal fin-rays in the specimen is 65, of the ventral 

 47. The characteristic tubercles of the adult turbot are not yet de- 

 veloped, but there are three little projections at the base of each of the 

 dorsal and ventral fin-rays, and also projections at the bases of the 

 caudal rays : these are probably the beginnings of marginal tubercles. 



The anterior end of the dorsal fin, and the basal tissue which carries 



