788 



SCANDINAVIAN FISHES. 



length to the end ot tlie initklle caudal rays, and the 

 greatest thickness is abuut half the greatest depth. Tlie 

 least depth is about S % (7'8 — 8"2 %) of the length. 

 The back is broad and convex, the belly more com- 

 pressed, forniii;g lietween the ventral tins and the anal 

 aperture a sharj) carina, covered witli a row of curved 

 scales. 



Tlie length of tlic head is about 23 — 21 % of that 

 (if tlie body. It is apparently a general rule that in 

 the young and the males the length of the head is 

 greater, in adult females less, than the greatest depth 

 of the body. In form the head is almost exactly si- 

 milar to that of the Bleak, but in old specimens its 

 upper surface, along the middle of the forehead and 

 the crown, is depressed and plane. The eyes are ver- 

 tically set, rather large, and situated almost entirely in 

 tiie anterior half of the head, the postorbital part mea- 

 suring about 48 or 44 % of tlie entire length of the 

 head. In s|)ecimens h — 8 cm. long the longitudinal 

 diameter of the eyes, which is sliglitly greater than or 

 equal to the vertical diameter, measures about 33 — 31 

 % of the length of the head, and is always perceptibly 

 greater than the length of the snout. The tip of the 

 snout is sharp (shallow), but broad (truncate), with a 

 shallow sinus to receive the point of the lower jaw. 

 The cleft of the mouth is turned sharply upwards and 

 rather large; but in consequence of its obliquity the 

 hind extremity of the maxillaries scarcely extends, when 

 the mouth is closed, to the perpendicular from the an- 

 terior margin of the eyes. The lips are thin. The 

 length of the upper jaw from the middle of the tip of 

 the snout is about 7 % (6'6— 7'2 %) of that of the body, 

 or about 30 % (29-2— 32-2 %) of that of the head. The 

 length of the lower jaw, which is generally about equal 

 both to the breadth of the interorbital space and the 

 length of the suture between tlie suboperculum and tiie 

 operculum, measures about 8"/g % (8'5 — 8'7 %) of the 

 length of the body, or about 38'/2 % (37-5— 40 %) of 

 that of the head. The nostrils lie rather near the up- 

 per anterior corner of the orliits. The gill-openings 

 are fairly large, the branchiostegal membranes coalesc- 

 ing with the isthmus in about a line with the hind 

 margin of the preoperculum. The outer row on the 

 front of the first branchial arch contains 11 — 13 pointed 

 gill-rakers, small and close-set below, larger and more 

 scattered above. The pharyngeal teeth are slender and 

 almost straight, with hooked tip and pectinated masti- 

 catory surface. They are sometimes set, according to 



Heckel, Maslowsky, and Sieuold, in two rows: but 

 in all the specimens examined by us they formed a 

 single row. The pharyngeal cartilage is elliptical, but 

 its hind (lowei') extremity is raised, as in the preceding 

 Leuciscines, in an inverted canaliculate form. 



The fins are of the normal Leuciscine type. The 

 dorsal Hn begins at a distance from the tip of the snout 

 measuring about half (49 — 52 %) of the length of the 

 body. The length of its base is about Vg (12—11 %\ 

 and its height about V7 (16 — 13^ 4 %), of the same length. 

 The anal fin is perceptibly longer and, especially in 

 old specimens, lower, and begins further back in the 

 females than in the males. The distance between it 

 and the tip of the snout measures in the males about 

 55 or 56 %, in the females aliout 57' , — 59', 2 %, of the 

 length of tiie body. Its base is about 16 — 14 % (in 

 exceptional cases 13 %), and its height in young spe- 

 cimens about 14 %, in old 13 — 12 %, of the same length. 

 Its length marks the approximation to the Abramidines, 

 for whereas in all the preceding Cyprinoids the least 

 depth of the tail is more than "/a of the length of the 

 base of the anal tin — though exceptions may occur 

 among young Minnows — in Lei(ca.sj)ii(s deliiieatus the 

 said ratio is less than "3 (about 50 — 61 %). The cau- 

 dal fin undergoes a similar change of growth, the length 

 of the middle caudal rays being in young specimens 

 about 12 %, in old about 10 — OV., %, of that of the 

 body. The longest caudal rays (in the inferior lobe) 

 measure about 22 or 23 % of the length of the body. 

 This fin is also subject to individual variation, an ex- 

 ceptional circumstance among the Cyprinoids, the num- 

 ber of the branched rays being either 16 or 17. The 

 pectoral fins are obliquely pointed and comparatively 

 short (16 or 15 % of the length of the body). The 

 ventral fins are almost triangular, and their length is 

 about 14 or 13 % (in exceptional cases 11 %), of that 

 of the body. The distance between the ventral fins 

 and the tip of the snout measures about 41 — 45 %, the 

 preabdominal length about 20 — 22 V2 ^> and the post- 

 abdominal length about 14 or 15 % (d") — 17 or 18 % 

 (?), of the length of the body. 



The anal aperture calls to mind the corresponding 

 organ in the Minnow and the 'Bitterling' (see above). " 

 It is more prominent and tubiform than in the Minnow, 

 especially in the females, and is furnished on each side 

 with an oblong, compressed papilla. 



The scales are thin, deciduous, and rather large, 

 their number in an oblique transverse row above the 



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