180 Dr. C. Lutken on the Vaag nicer and 



and 1 : 2*04; but it is quite exceptionally that the tail (from 

 the anus) is a little longer than head and body together, so 

 that the anus comes to be situated before the middle of the 

 total length instead of, as always elsewhere, behind it. 



The length of the head (from the apex of the closed mouth 

 to the posterior margin of the operculum) is contained from 

 about seven to about nine times in the total length ; it seems 

 to be relatively small in the larger specimens and great in 

 young examples. 



The greatest height of the body is contained about four and a 

 half to six and a half times in the total length. That the 

 height decreases proportionally with the age, at least to a 

 certain point, to increase again in older individuals, although 

 it may seem probable, does not appear from the measurements. 



The size of the eye (diameter of the orbit) is contained from 

 three to four times in the length of the head, and seems, as 

 indeed is generally the case, to undergo a relative diminu- 

 tion with age. 



The rays of the dorsal fin vary in number from 154 to 186 

 (besides the rudimentary nuchal fin-rays). In very young 

 individuals (0*830 metre) they are rather rough to the touch 

 in their lower part j in older specimens this roughness has 

 disappeared, except the spine at the base. Their average 

 elevation (determined by the length of a ray directly over the 

 anus) is, in proportion to the greatest elevation of the body, 

 between 1 : 1*7 and 1 : 3*3, and may therefore vary between 

 more than one 'half and scarcely one third of that measure- 

 ment ; it is on the average relatively higher in the young and 

 lower in the older fishes. The number of pectoral fin-rays 

 may be from ten to thirteen. 



The caudal fin-rays are in general eight, and only excep- 

 tionally seven in number ; they may be rough, especially in 

 young individuals, and chiefly the first and last The height 

 of the caudal fin (t. e. the greatest length of its rays) is, in 

 proportion to the total length, as 1 : 5'5 to 1 : 10*7 ; it may 

 therefore be relatively twice as great in some as in others, in- 

 dependently of the injuries to which it is exposed at all ages : 

 it seems on the whole to be relatively highest in young and 

 lowest in old specimens. Perhaps also the root or peduncle 

 of the tail is, as a rule, relatively shorter in the younger 

 specimens ; but its limit towards the wider part of the caudal 

 fin is often impossible to determine, when the two pass gra- 

 dually into one another. The caudal fin can in general lie 

 directly backward; and this position is perhaps quite as 

 natural as the nearly vertical position. In the rudiment of 

 the anal fin the normal number of ray- is certainly five, 



