78 



SCANDINAVIAN FISHES. 



latter". The lon.iz', pointed caudal lobes are the result 

 of considerable changes due to age, but sometimes seem, 

 according to Lutken's figure (1. c, tab. IV, fig. 1), 

 to be formed at an early period''. The changes of age 

 as ^vell as individual peculiarities cause remarkable va- 

 riations in the dental equipment of the mouth. A young 

 specimen, 56 mm. long, has in the upper jaw an outer 

 row of large teeth, and inside this in the back ])art 

 one row and in front two irregular ro^\'s of smaller 

 teetli; in the lower jaw there are two pairs of large 

 canine teeth in front, belonging to the inner row, which 

 throughout is made u]) of larger teeth than the outer; 

 on each palatine bone is a row of small teeth, but the 

 vomer is without t^eth. Lunel has, however, remarked 

 (1. c, pp. 171 and 172) the irregularity of the occur- 

 rence of the teeth on the vomer and the occasional 

 shedding of the jaw-teeth, which leaves only the outer 

 row iu^ each jaw. The spines at the margin of the 

 preoperculum still exist in specimens 56 mm. in length, 

 where 12 of them may be counted, though they are 

 indistinct. 



The ditt'erences between the scales on difterent 

 parts of the body are highly remarkable. The snout, 

 the anterior ])art of the forehead, the inter maxillaries, 

 and tlie margin of the hind lower corner of the pre- 

 operculum are the only scaleless parts of the body. 

 In younger specimens the boundary of the scaly part 

 of tlie head begins vertically above the posterior 

 third of the eye and runs fairly straight down tlie 

 sides, but in older specimens it begins above the 

 anterior orbital margin and on the sides of the head 

 runs obliquely downwards and back-wards to the hind 

 upper part of the orbital margin. Winther' has 

 pointed out the resemblance to the Sparidce in the pores 

 which pierce the scaleless skin, and he also refers to 

 the same system of sensoiy organs (the sj'stem oi the 

 lateral line) the pores in the scales which occur in this 

 species as in Pferijcomhus (see fig. 20 al)ove). The 

 distribution of the different kinds of scales is also es- 

 sentiall}' the same as in the latter species; but in Ray's 

 Bream the lateral line, which from the ujiper corner 



of the gill-opening roughly follows the curve of the 

 back, forms, at least in the anterior part of the body, 

 a well defined boundary between the smaller and more 

 rounded scales of the back and the higher (broader) 

 scales of the lower parts of the body. The former are 

 in old specimens smooth and perfectly cycloid, but in 

 younger specimens the radiating striations on these 

 scales, as Lutken'' remarks, are granular or even spi- 

 nous and give the scales a ctenoid character. On the 

 lower (broader) scales Lilljeborg' was the first to 

 remark the spine in the middle of each scale, which 

 disappears with age. In our smallest specimen (fig. 23) 

 these spines are especially distinct on the lower parts 

 of the ventral sides proper, and between the ventral fins 

 and the vent they make the ventral edge dentated as 

 in the Sprat. In older specimens, where the spines 

 have disappeared, the scaly covering of the belh' and 

 the pectoral (shoulder-) region is remarkable for its 

 closer resemblance to the scales of the back and head, 

 and b}' this contrast to the covering of the other lateral 

 parts reminds us in some ^vay of tlie corslet of the 

 true ScomhridcF. 



Owing to these differences lietween the scales of 

 the body, we have above omitted, in the usual fin and 

 scale formula, to give the number of scales in the la- 

 teral line. In our smallest specimen we find 61 trans- 

 verse roAvs of dorsal scales and about 50 in a straight 

 line lielow the lateral line; in an older specimen 90 

 transverse ro-ws of dorsal scales, and above the lateral 

 line, counting obliquely downwards from the beginning 

 of the dorsal fin, 14 scales in one of these rows, below 

 the lateral line 16, thus making in all 31 longitudinal 

 rows of scales. 



The colouring of the l^ody is brownish Avith a 

 silver or tin-white gloss; laut the dorsal edge and the 

 membrane of the vertical fins where it is free from 

 scales at the margin, are blacker, the caudal fin, 

 however, being edged with white at the hind mar- 

 gin. To judge b}' v. Wright's drawing of a fresh 

 specimen the black colouring also extends over the 

 snout and branches sideways along the depression 



" In the siiiullor gpccimcn mentioned above, the length of the pectoral fins is almost 30 % of the length of the body and of 

 ventral almost 12 »«; in the larger specimen these proportions are respectively 33 % and 8 %. 



'• In tlie smaller specimen nienlioiicd above, the length of the middle caudal rays is about 42 % of that of the longest ones, and 

 fin is thus much less deeply forked than in LtlTKEN's figure, the original of which, however, was younger or at least smaller, while in 

 larger specimen mentioned above, the length of the middle rays is only 18 °„ of that of the longest. 



' Zool. Dan., 1. c. 



<* 1. c., p. 495. 



' Om Pterijcombus braina. 1. c: — cf. also L(Jtken, 1. c, pp. 495 and 406. 



the 

 the 



