784 



SCANDINAVIAN FISHES. 



(varying between 23 and 2.5 ?a), and the greatest thick- 

 ness at most about ' ,, (varying between 8 and 11' o 

 %), of the length of the body to the end of the middle 

 caudal rays; but in gravid females (.see the figure) the 

 former ratio may rise to 27V\, %. The least deptli of 

 the tail is about Vu, (varying between 9 and 10'/^ %) 

 of the length of the body. 



The l^ack is arched at the occiput, but elsewhere 

 slopes almost in a straight line, })oth backwards and 

 forwards from its apex at the begiiuiing of tlie dorsal 

 fin. Just in front of this fin it is very slightly 

 compressed at the margin, but with this exception it 

 is convex or even (behind the doi-sal fin) flat. The 

 belly descends from the cliin in a regular curve, rather 

 sharp in gravid females; and the ventral margin is 

 broad and flatly convex, but furnished between the 

 ventral fins and the anal aperture 1) in the median 

 line with a distinct, but low cai-ina, composed of curved 

 scales of a special type, and 2) at the boundary be- 

 tween it and the sides with a similar carina, usually 

 less prominent, but sometimes quite distinct, which runs 

 back on each side from the outer angle of the insertion 

 of the ventral fin. 



The head is middle-sized, but laterally compressed, 

 its length being in young specimens somewhat gi-eater, 

 in old less, than the greatest depth of the body, and 

 varying between 24 and 22 % of the length of the 

 latter. The clieeks are flat and perpendicular; the up- 

 per surface is straight and slightly convex or almost 

 flat with a gentle slope in a forward direction; and 

 the breadth of the interorbital space measures in young 

 specimens 31 % of the length of the head, but rises in 

 old to at least 35 ?6 of the same. The eyes are set 

 high on the sides of the head, and are comparatively 

 small, being about equal in size to those of the Tench. 

 They invariably lie in tlie anterior lialf of the head, 

 for the postorbital length tliereof measures in young- 

 specimens about 56 %, in old about 63 % of its entire 

 length from the tip of the snout. In young specimens 

 about 16 cm. long the length of the eyes, which is al- 

 ways somewhat greater than their vei'tical diameter, is 

 about 21 — 20 % of that of the head. In specimens 

 18 — 22 cm. long this proportion has sunk to 18 or 

 17 %, and in specimens 44 — 66 cm. long the length 

 of the eyes is oidy about 14 — 12'/^, % of that of the 

 head. The lengtli of the snout, whicli is shallow and 



wedge-shaped, tapering to a sharp edge in front, mea- 

 sures about 28 % (27—29 %) of that of the head. The 

 lines of the mouth are characterized principalh- by the 

 sinus at the tip of the snout, into which the more or less 

 knub-sliaped point of the lower jaw fits when the mouth 

 is closed. On each side of this sinus the labial mar- 

 gin forms a somewhat arcuate projection, thus giving 

 to the margin of the upper jaw on each side the elong- 

 ated S-shape pointed out by Nilsson. The lower jaw 

 expands in a similar manner on the sides in front; 

 and the fleshy lips, especially the lower, are tumid at 

 the corners of the mouth. The intermaxillaries cannot 

 be protruded beyond the tip of the snout; yet the gape 

 is large in consequence of the length of the jaws, which 

 is greater, com})ared witii the size of the head, tlian 

 in any other Scandinavian Cyprinoid", the length of 

 the up])er jaw from the tip of the snout being about 

 38 % (36—39 %) of that of the head, and tlie length 

 of the lower jaw about 48 ?& (45 — 51 %) of the same. 

 There is no free tongue; but the middle part of the 

 hyoid apparatus in front (the glossohyoid region) is 

 flesliy and soft. The nostrils are set on a level with 

 the upper orbital margins, aljout twice as near to the 

 eye as to the tip of the snout. The gill-openings are 

 large, the broad branchiostegal membranes not coalesc- 

 ing with the isthmus until they reach the perpendicular 

 from the hind margin of the eyes. Nine or ten short 

 and scattered gill-rakers, compressed at the ti]) or with 

 faint signs of digitation (cf. the Ide), compose the outer 

 row on the front of the first branchial arch. The outer 

 margin of the ])]iMryugeals is fui'uished witli 7 or 6 

 pointed and still shorter gill-rakers. The long pha- 

 ryngeals (fig. 194) are armed, as mentioned above, with 

 two ro^vs of simple, but strong teeth, hooked at the 

 tip. The pseudobranchiffi lie high on the inner surface 

 of tlie hvomaudibular bone, in the hollow on each side 

 above the 'carp-tongue', and in some cases are there- 

 fore difficult of detection, though well-developed. 



All the fins save, in some degree, the ventrals are 

 distinguished by a more or less incised, pointed form. 

 The dorsal fin begins at a distance from the tip of the 

 snout measuring on an average 4772 ^ ("^'^Va — 48 '/g %) 

 of the length of the bodj'. Its base occupies about Vio 

 (9'3 — iri %) of the same length, and its height is in 

 young specimens about 18' ., %, in old about 16 "», of 

 the same. Tlie anal fin, which lies further back in the 



" Comjiared with (lie length of tlie body, liowever, tlie jaws of the Gokitieh are equally loug. 



