940 



SCANDINAVIAN FISHES. 



and only a little shorter than the second, which is the 

 longest in the fin and branched like the remaining 9 or 

 10 rays, which rapidly and regularly deci-ease in length 

 towards the bottom of the fin. In the ventral fins the 

 first (outermost) two rays are simple, the first ray 

 being, however, extremely small (rudimentarj'). The 

 second simple ray is but slightly shorter than the third 

 ray, Avhich is branched and only a little shorter than 

 the next, the length of which is equal to, or only a little 

 less than, that of the tliird and fourtii branched rays. 

 The other branched rays (5th — 7th) gradually decrease 

 in length. Along the inner margin of the last i-ay runs 

 a thickened growth of fin-membrane, with the appear- 

 ance of a defectively developed ray. The utider sur- 

 face of the ventral fins seems, like the sides of the 

 caudal fin, to be clothed with elongated scales. 



The whole body is densely covered with scales, 

 which extend forward on the head over the whole intei- 

 oi'bital space, but are deciduous, the specimens taken 

 being generally scaleless, or with only a part of the 

 lateral line left. The scales (fig. 234, «) are thin, trans- 

 parent, and flexible, rather large and of equal size, 

 rounded or of a broad elliptical shape, set in the trans- 

 verse direction of the body (with the vertical diameter 

 greater than the horizontal); their nucleus is central; 

 they are furnished with dense concentric stri:v and a 

 few (4 — G) grooves radiating forwards and backwards. 

 These grooves, between which the concentric stria? (thick- 

 ened and elevated lines) are sharply curved, render the 

 anterior margin of the scale sinuate, the posterior (free) 

 margin irregularly erose. In the nucleus of the scale and 

 the immediate neighbourhood of the nucleus, as well as 

 in an angular patch coinciding with the margin of the 

 demnal follicle, the concentric striae are joined at right 

 angles by transverse sti'ia?, and in the hind (free) ]3a,rt of 

 the scale they are irregularly broken uj) here and there, 

 crossing each other in a network. The scales of the 

 lateral line (fig. 234, h) have a short, pear-shaped duct 

 at the centre of their outer surface, and are indented 

 in a heart-shaped form, but deeply, at tiie hind (free) 

 margin, by a narrow sinus, which widens, however, in 

 front (towards the centre of the scale) in a stilliform 

 manner. Pointed and elongated scales appear not onlj^, 

 as we have mentioned above, on the sides of the caudal 

 fin and the under surface of the ventrals, but also in a 

 row along the base of the dorsal fin, where they are 

 more or less deformed (fig. 234, c), as if they were 

 only half-scales, with laterally set nucleus and an in- 



creased number of grooves (about 9) oblitpielv radiatincf 

 towards the anterior margin. 



According to Costa's figure the coloration of the 

 whole dorsal side (including the upper part of the head) 

 and the lower posterior part of the tail is brownish red, 

 of the opercular apparatus shifting gi-een and black, of 

 the ventral side dark brown, of the sides of the head 

 silvery. The few scales still adhering to the specimen 

 kindly lent us from Christiania Museum suggest that the 

 silvery lustre extended throughout the sides of the body; 

 but where the scales are wanting, the skin of the sides 

 (in spirit-preserved specimens) is also brownish red. 

 Back from the occiput, sometimes to a line with the 

 adipose fin (according to Storm), there run on each side 

 one or two rows of orange spots, caused, according to 

 CoLLETT, by the fact that each scale in the two rows 

 next above the lateral line bears a similar spot at its 

 tip. These spots are visible, however, though faint, in 

 the skin, after the scales have dropped off". Costa 

 figures some of them, along the base of the dorsal fin, 

 as luminous spots. 



The true luminous spots are here (in spirit-pre- 

 served s]iecimens) of a greenish lustre. The largest on 

 each side lies on the lower part of the hind preoper- 

 cular margin. The three spots belonging to each hyoid 

 arch we have already mentioned. The remaining spots 

 are arranged, in the specimen now before us, as follows. 

 Behind the shoulder-girdle, down to the isthmus, where ' 

 the lowest spot lies just behind the posterior extremity 

 of the lower jaw, runs a row of spots, the thii-d from 

 above being situated at the lo^\'er angle of the pectoral 

 fin. In front of the ventral fins (on the preabdominal 

 region) we find, on each side of the median line of the 

 belly, a row of 3 luminous sjjots, and up the side of 

 the body this row is continued obliquely backwards by 

 a spot just before the outer angle of the insertion of 

 the ventral fin and another set halfway up to\vards the 

 lateral line. Behind the ventral fins (on the postabdo- 

 minal region) there runs, on each side of the median 

 line of the belly, from the hind (inner) angle of the 

 insertion of the ventral fin to a line ^vith the anal aper- 

 ture, a row of 5 spots, and this row is continued up 

 the side of the body by 3 spots, the uppermost of which 

 is set on the lower ])ortion of a scale in the lateral 

 line. Along each side of the base of the anal fin is a 

 row of 9 spots, and on the lower part of each scale in 

 the lateral line above the end of this row there lie 2 

 spots. After a break measuring twice the distance be- 



