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416 MR. E. AV. L. HOLT STUDIES IK [May 1, 



of the body. The length of the eye, greater than its height, con- 

 tained about five times in the length of the head, and once and a 

 half or nearly twice in the length of the preorbital region. The 

 length of the eye always greater than the width of the mterorbital 

 space, which is usually less than the height of the eye, but may be 

 equal to or even a little greater than that measurement. The 

 lower jaw the longer, projecting beyond the snout, the barbel small, 

 much less than the length of the eye. The height of the caudal 

 peduncle less than the height of the eye. The vent opposite about 

 the seventh or ninth ray of the second dorsal. The mouth more 

 or less closely speckled with black chromatophores. 



The italics are intended to denote such characters as serve at a 

 glance to distinguish this species from the Common Ting (31. 

 vulgaris, Fleming), and the close resemblance which the Birkelange 

 bears to that well-known form renders it unnecessary to elaborate 

 the diagnosis further. 



The diagnosis is based on the examination of the seven specimens 

 forming the subject of this note, which range in total length from 

 42 to 50| inches. Hence it may not be strictly applicable to 

 smaller examples, since the proportions, especially those of the eye, 

 are subject to developmental changes in all fish. I am led by this 

 to suppose that Lilljeborg, who describes the mterorbital space as 

 much less than the height of the eye, may have based his remarks 

 on the examination of smaller fish ; but it is quite possible that a 

 variation in this, as apparently in some other respects, exists 

 between Scandinavian and more Western examples of this species. 



The condition exhibited by my specimens renders it also probable 

 that the relative length of the lower jaw increases with the size of 

 the fish, so that in young examples it may even be less than that 

 of the upper jaw 1 . We know this to be the case in the Coal-fish 

 ( (Indus virens), in which the lower only passes the upper jaw when 

 a length of about twelve to fifteen iuches has been attained. 

 There remain, however, other characters sufficiently well marked 

 to distinguish the species at any size. The Birkelange is not 

 known to reach a length greater than 60 inches 2 , and is therefore 

 a much smaller fish than the Common Ling. 



1 It may be remarked that very large Common Ling occasionally exhibit an 

 infinitesimal projection of the lower jaw. Such a projection is given by Lillje- 

 borg as a specific character in the case of the species before ns. Smitt, however, 

 states that in all his specimens the upper jaw was distinctly the longer, and his 

 figure (op. tit. pi. xxvi. fig. 3) shows this condition clearly enough. From 

 internal evidence the material forming the subject of his remarks seems to have 

 consisted of four examples, stated to be adult, ranging in size from 56'2 to 

 828 cm., and therefore all smaller than our Iceland and Faroe specimens. It 

 is, nevertheless, by no means clear that all small examples have the snout pro- 

 jecting, as Lilljeborg (op. eft. iii. Append, p. 787) mentions an example of 

 (50 cm. without qualifying his previous remarks on the conformation. On the 

 whole it seems most probable that the majority of adults, whether from Scan- 

 dinavian or other waters, have the lower jaw the longer. 



2 Smitt (pp. tit, p. b'2'2) observes that the species seldom exceeds a length of 

 one metre (89 inches cct.), but it does not appear that his acquaintance with 

 this fish is very extensive. 



