Holt and Calderwood — Report on the Rarer Fishes, 507 



This is the only flatfish known to descend beyond a depth of 500 fathoms. It 

 has been recorded by Goode, from off the Atlantic coast of the United States, at 

 depths of 120, 263, 395, 603, and 732 fathoms ; by Collett, off Lofoten and Fin- 

 mark, at 125 to 150 fathoms ; by Strom, in Trondhjem Fjord, at 200 fathoms ; 

 and by Bourne, off the S.W- of Ireland, at 200 fathoms. During the Survey 

 three specimens, from 5 to 6 inches in length, were trawled at 144 fathoms, and 

 four others, larger, but of no great dimensions, were taken at 220 fathoms. The 

 species was also met with in littoral waters {vide " Sci. Proc," vii., pp. 343, 

 409, 447). 



In the large size of the eyes, and comparative slendemess of the structural 

 pai'ts, P. cynoglossus bears a certain resemblance to R. megastoma, and it may be 

 ^id that the two species have very much the same vertical distribution on our 

 own coasts, the former occurring most abundantly on the east, and the latter on 

 the west coast. In northern latitudes craig-flukes are found in quite shallow 

 water, as at Iceland,* as well as at the considerable depths noted above ; but the 

 species does not appear to have been met with by the French " Travailleur " and 

 "Talisman" expeditions at any depth in the South Atlantic; and the Bay of 

 Biscay, where it is known to occur, at moderate depths, in some numbers, is 

 perhaps the southern limit of its range. 



Collett {op. cit. p. 15l) was the first to demonstrate that P. elongatus, Yarrell., 

 is merely a young stage of P. cynoglossus. In dealing with the development of 

 the species in a former number of these "Transactions" {t. c. p. 88, pi. xv., 

 fig. 124) an example, illustrative of the P. elongatus stage, has been given by 

 one of us. 



Genus Solea, Klein. 



Solea vulgaris, Quensel. The Common Sole. (Deep-sea.) 



Solea vulgaris, Vaili-ant, "Exp. ScL Trav. Talism., Poiss,," p. 189. 



The sole must be admitted into the category of deep-sea forms on the strength 

 of the capture of a specimen by the French scientific expedition, at 127 fathoms, 

 on the Banc d'Arguin. The species is well known to congregate in certain of the 

 deeper parts of the North Sea in hard winters. The Great Silver Pit, the most 

 noted of these grounds, has a maximum depth of about 60 fathoms, which is, 

 we believe, with the exception referred to above, the greatest depth at which soles 

 are known to have been taken. • 



* Vide «' Joum. M, B. Assoc," iii. 1894, pp. 130, 132. 



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