I'OLI.AfK. 



505 



iiess) being about half tho doptli. la old Pollacks the 

 greatest depth of the body is '22 — 25 % of its length, 

 in young ones about 19 or 20 %. The head, the length 

 of which is about 25 or 2(5 % of that of the body, is 

 of a handsome, cuneiform sha])e, with depressed fore- 

 head, sloping quite evenly to the lii'oad, rounded tip 

 of the snout, which is quite thin and low. The sides 

 of the head are flat, and almost parallel right out to 

 the snout. 



The louver jaw is always distinctly longer than 

 the upper, somewhat pointed, and is the extreme tip 

 of the wedge formed by the head \vhen the jaws are 

 closed. The length of each lirauch of the lower jaw 

 is between about \\ % (in Aoung specimens sometimes 

 slightly less) and ISVa ^'' of the length of the l)ody or 

 about 57 — 60 % of that of the head. The upper jaw 

 is not protruded when the mouth is opened; and when 

 the mouth is closed, the maxillary bones are almost 

 entirely concealed by the labial fold that unites the 

 margin of the snout to the suborbital ring. The hind 

 extremity of the maxillary bones extends to the per- 

 pendicular from the anterior margin of the eye, and 

 lies at a distance from the tip of the snout equal to 

 about 10 .1/ of the length of the body or 65—70 % of 

 that of the lower jaw. 



Fine, pointed teeth of uniform size are set in a 

 card on the intermaxillary bones and in a simple or 

 (in front) double row in the lower jaw and on the 

 head of the vomer. The tongue is of an oblong, tri- 

 angular shape, rather soft, and with long, free tip. 

 The branchiostegal membranes of both sides of the body 

 are united inferiorly into a free fold, so broad that the 

 margin at the middle extends almost to a line with' 

 the hind extremity of the lower jaw. 



The eyes are round, and measure ^'j — ','5 of the 

 length of the head, according to the age of the speci- 

 men. Their position is such that the line drawn along 

 the middle of the body to the tip of the upper jaw 

 passes somewhat above the centre of the pupil, which 

 lies a little in front of the middle of the head. The 

 length of the snout is Ijetween about 75 % (sometimes 

 70 %) and 78 % of the postorbital length of the head. 

 The distance between the eyes is about 65 — 75 % of 

 the length of the snout, and in young Pollacks is less, 

 in old greater, than the longitudinal diameter of the eyes. 

 The nostrils are set in the last third of the length of 

 the snout. The hind margin of the anterior nostril on 

 each side is raised into a cucullate dermal flap, which 



Scandinavian Fishes. 



may be dropped forward like a lid over the small 

 aperture. The posterior nostril is larger, but without 

 any elevation of the margin. 



The whole head, with the exception ot the jaws, 

 is covered with scales, though these scales are smaller 

 than those of the body. In old and middle-aged Pol- 

 lacks the length of the head is about 25 or 26 % of 

 that of the body, in very small specimens .somewhat 

 greater. 



The body is entirely covered with small, thin, and 

 imbricated scales, set very densely and firmly attached 

 to the skin. These scales are, however, indistinct until 

 the skin is partly dry, or the slime has been removed. 

 The lateral line is of exactly the same structure as in 

 the Whiting, and forms the same upward curve from 

 behind, below the second dorsal fin. 



The anal aperture is situated a little behind the 

 end of the first third of the length of the body, below 

 the last third of the pectoral fins, or somewhat behind the 

 perpendicular from the beginning of the first dorsal fin. 



The top of the insertion of the pectoral fins lies 

 half-wav up the body. These fins are rounded at the 

 tip and contain 2 simple and (generally) 17 Ijranched 

 rays. The -whole base is covered with scales. The 

 ventral fins are still smaller than in the Coalfish, their 

 length being about 672 ^ of that of the body, and 

 varying to such an extent that in young Pollacks it is 

 about half, in old considerably less than halt, of the 

 distance between their insertion and the beginning of 

 the anal fin, a distance which increases Avith age from 

 about 13 or 12 % to nearly 16 :?5 of the length of the 

 body. They are set somewhat in front of the pectoi'al 

 fins, and are made up, as usual, of 6 rays, the first 

 two simple or the second indistinctly cleft, the others 

 branched at the tip. None of these rays has a long, 

 free tip, and the third ray is the longest. 



The three dorsal fins are of normal structure, 

 rather thick, and covered with scales. The first begins 

 at a distance from the tip of the snout measuring 33 

 or 34 ?o of the length of the body, and the length of 

 its base is about 9 — 11 % of the same length. The 

 first two or three rays are simple, but soft at the tip, 

 and the third or fourth ray is the longest, its length 

 in young Pollacks being usually rather more, in old 

 rather less, than the postorbital length of the head. 

 The fin-membrane is entirely covered with rather fine 

 scales out to the margin. The second dorsal fin be- 

 ^ns at a distance from the tip of the snout equal to 



64 



