928 



SCANDINAVIAN KISIIF.S. 



braiie by which they are comiectccl. Tlie adipose Hn 

 behind the dorsal fin is l(jng and low. 



The anal fin, which begins just behind the vent, 

 is longer but lower than the dorsal fin pro])er, and the 

 hind part of its margin is deeply concave. The distance 

 between it and the tip of tlu; snout is about Gl — 63 % 

 of the length of the body, and its base measures about 

 17 — 18 % of the same. In the distribution of the rays 

 we observe that the first seven and the last four are 

 set more or less close togetlier at the base, but tliat 

 the eighth ray is more widel)- separated both from 

 the seventh and the ninth, and points straight down- 

 wards, its direction tlnis converging with that of the 

 seventh ray. 



The caudal tin is deeply forked. The length of 

 the middle rays is 8 % of that of the body, and ap- 

 pears to be perceptibly less than half (at most about 

 46 "o) of that of the longest rays. At the upper mar- 

 gin uf tlie fin lie 9, at tlie lower 6, shoi't but com- 

 paratively thick and hard su])porting rays, the anterior 

 directed outwards (respectively upwards or downwards). 



In the suspensory apparatus of the pectoral fins, the 

 iil>perniost bone, probably answering to the suprA-cla- 

 vicular l)one — in which case the posttemporal bone is 

 wanting — is bent at a right angle. Its upper, shorter, 

 horizontal arm is straight and of uniform breadth, 

 attached to the median line of the occiput — not at 

 the side, where the posttemporal bone is attached in 

 other fishes — and its lower, vertical arm, which is 

 somewhat bi'oader and forms a thin expansion in front, 

 rests u])on the upper part of tlie clavicle. The angle 

 between the arms forms a shoi't spine, directed back- 

 wards, and both arms are coursed on the outside by 

 a longitudinal groove, bounded by ridges and hollowed 

 into grooves similar to those in the upper part of the 

 temporal region (see al)ove). The ridges and grooves 

 are continued on the outside of the vertical part of the 

 clavicle in front of the pectoral fins, and below the 

 latter the clavicle sends out, in the skin, a backward 

 process, flat and of uniform breadth, but curved up- 

 wards like a sabre, and with similar grooves on the 

 outer surface. The inferior part of the clavicle ex- 

 pands forwards and inwards to a thin, vertical blade, 

 projecting straight downwards in a pointed spine, which 

 marks the limit between the sloping istlimian region 



and the jiorizontal ventral margin. Tlie pectoral fins 

 are obliquely set; when at rest, thev point upwards 

 and backwards. Thej- are rather long, but narrow and 

 obliquely pointed. The third or the fourth ray is the 

 longest, liiit only slightly longer tlian tiie second. The 

 first ray, which is the only simple one, is a little 

 shorter than the second; the last (10th) occupies about 

 ^/j, of the length of the fin, which measures someAvhat 

 more than '', (26—27 ^) of that of the body. 



The ventral fins are set undei'inost on the ascend- 

 ing break in the ventral margin, with their insertions 

 close together and vertically situated, the first ray, 

 which is simple but, like the others, compressed, being 

 thus the lowest, and the under side of these fins in 

 other fishes being here turned inwards". In shape the 

 ventral fins are oval, and their length is about equal 

 to the height of the anal fin, 8'/.— O'/o % of the length 

 of the body. The lowest point in their insertions 

 lies at a distance from the tip of the snout measuring 

 nearly Vs (62'/2— 65 %) of the length of the body, 

 and the distance between this point and the foremost 

 ])oint in the insertions of the pectoral fins (the pre- 

 abdominal length) is about 29 — ;-5() % of the same 

 length. The postabdominal length, which ascends but 

 breaks off at an angle, measures in a straight line 

 about HVs — 1'> "'o of the length of the body. The 

 thin pelvic bones, which are vertically set, share in 

 the structure of the septum between the luminous spots 

 of the preabdominal margin. But at the lower poste- 

 rior corner each of the pelvic bones projects in a spine, 

 and sends out above this spine an ascending process' 

 Avhich joins the lower part of the hindmost preabdo- 

 minal rib, while the lower tips of the preceding ribs 

 touch the squamous growths that enter into the struc- 

 ture of the sharp ventral margin and bear its lumi- 

 nous spots. 



The greater part of the body — except the black 

 or grayish brown back — is covered with a thin, sil- 

 very skin; but according to v. DCben and Koren 

 scales arc also present, though these are thin and deci- 

 duous. "These scales are rather large (about 2V2 m™- 

 long in a specimen 60 mm. in length), smooth with 

 entire margin, and of a bright silvery lustre like their 

 underlayer. Under the microscoi)e they gleam with all 

 the colours of the rainbow, but not even then does 



" This is also the case, as we liave seen above (p. 426), in Bolhina, Init is tliere liue to an entirely different slnictnral peculiarity. 

 ' Cf. the analogous stnielnre in the Sticklebacks, see above, p. 035, tig. l.')7, ,-1, vs. 



