780 



SCANDINAVIAN FISHES. 



80 — 36 i-in., still Mttiiins ;i wciirht of ahoiit 1 ko'in." 

 In external i'nytn it seenis to occup\' an iiiteriiii'diate 

 position between the Leu<is(_ines and the Crucian ("arp, 

 which it so closely resembles in this respect that in 

 some localities it bears the name of Sjormla (Lake 

 Crucian Carp). In Halland and Blekiiige it is also 

 callcil lliidd (llu(i), and on the Scanian coast of the 

 Sound it is kiio\Mi \)\ its Danish name of liiid^knUe 

 (I);ui. skallc. lioacli). The body is deeper and, in pro- 

 portion to the depth, more compressed than in the pre- 

 cediui;- Lcuciscines, the Greatest dejith being about V:/ 

 of the length to the middle fif the caudal tin in young 

 specimens, in old somewhat less than "4" of the same. 

 In tliis respect, however, the Kudd undergoes a change 

 of growth \\hich during }'outh ranges it close beside 

 the Koach in a more developed state''. The greatest 

 thickness is about 32—42 % of the greatest depth. 

 The least dei^th of the peduncle of the tail measures 

 about ' i„ (8—11 %) of the length of the body. The 

 back rises somewhat abru]Jt]^■ from the occiput, form- 

 ing a regular cur\ e to the beginning of the dorsal tin, 

 where it bends at an obtuse angle, and then descends 

 in ail elongated S-shaped curve, or sometimes almost 

 in a straight line, towards the base of the caudal tin. 

 It is convex throughout the greater part of its length, 

 but in front of the dorsal fin compressed at the mar- 

 gin, as in the Roach. The belly is rather strongly 

 compressed, but flat to the ventral fins, then carinated 

 to the anal aperture. It runs in an unl)rok(>n curve 

 from the chin to the vent, where it forms an angular 

 bend, and then rises almost in a straight line to the 

 peduncle of the tail. 



The head is of moderate size, measuring about '/s 

 of the length of the body', and compressed, with broad 



and almost straight forehead' and small, blunt, flattened 

 snout". The mouth is small* and turned upwards, the 

 lower jaw being somewhat longer than tlie upper, so that 

 the tip of the chin is the most prominent jwint. The 

 eyes are somewhat larger than in the Roach, their 

 longitudinal diameter measuring in middle-.sized Rudd 

 about 23 %' of the length of the head. Their ])ositiori 

 is such that the line from tlie middle of the caudal fin 

 to the margin of the upper jaw cuts the centre of the 

 pupil; and in adult specimens tiie postorbital length of 

 the head is equal to or a little greater than half the 

 entire length thereof, but in the fry sometimes only 

 about 43 % of the same. The nostrils are similar to 

 those of the Roach. The gill-rakers also resemble those 

 of the Roach; but the pharyngeal teeth (tig. 193) are 

 .set in two rows, ■^ in the inner and 3 in the outer, 

 their masticatory surface is coursed by transverse grooves 

 on the sides and granulated (pectinated) at the margin, 

 and the pharyngeal cartilage is furnished on the sides 

 with oblique, transverse grooves. 



The dorsal tin occujiies the same backward posi- 

 tion as in the Minnow, the Owsianka, the 'Asp', and 

 some s[iecimeiis of the Dace, l3'ing opposite, not to the 

 ventral tins, as in the other Leueiscines, but to the 

 space between the ventral and anal tins, as in the 

 Abramidines. It begins at a distance from the tip of 

 the snout measuring about 52 — 56 % of the length of 

 the body; and the distance between the ventral tins 

 and the same point is only about 79 % (78 ?») — 84 % 

 (85 %) of the former distance. The form of the tin, 

 on the other hand, is the same as in the rest of our 

 Leueiscines, the length of its base measuring about 

 11 — 13 % (13';, %), and its height about 20— 17 % of 

 the length of the body. The anal fin is distinguished 



i 



" According to tin- reports sent in to tlie Swotlisli Fislieries Coniniiltee of 1881 — 83 the KiiddCO m.iy iittain !i length of l' ., Sw. feet 

 (45 cm.) and a weight of 4 Sw. pounds (1,700 grammes). D,\y tells ns of a specimen from Norfolk 3 Ihs. I oz. (l,38'.l grammes j in 

 weight. According to Fatio the Rudd weighs at a length of 15' ^ cm. 45 grammes, at a length (if 2ii6 mm. 230 grammes, and at a 

 length of 3 dm. more than ' ., '^'1"- 



' 26—36 %. 



' 86 — 39',., °i, according to our measurements. 



'' In a Roach IfiT mm. long the greatest depth was 26'3 'i, and the greatest thickness lO'S \, of the length of the body. Iti n 

 liudd Ij3' „ mm. long these percentages were respectively 26'8 and ll'O. 



'■ About 23 — 20 % (19-8 %) of the length of the body in Rudd 03 — 277 mm. long. 



■' The breadth of the inlerorbital space increases with age in the specimens just mentioned from .ibout 40 to 47 °. of the length of 

 the head. 



" In the same specimens the length of the snout varies individually, though generally increasing, from about 28 % (in e.xception.il 



cases 2i; %) to 33V2 ''■' "^ ^''^^ "^ ^'"^ '"^"''• 



'' The length of the upper jaw from the middle of the tij) of the snout varies in the same specimens between about 28 li (exceptionally 

 27 »=) and 32 % of that of Uie head, and the length of the lower jaw between 39 and 36 °i (34 °.) of the same, being in young specimens 

 often cipial to. in old ahvays less than, that of the suboperculum. 



' In our smallest specimen, 03 mm. long, the longitudinal diameter of the eye measures 32 % of the length of the lie.ad, in our 

 argest specimen, 277 mm. long, 21 % of the same. 



