1002 



SCANDINAVIAN FISHES. 



The ce])lialic' system of the lateriil line has very 

 distinct and deep pores in the thick skin. In each 

 t'ronto- rostral brancli tlierc nsuall)' appear 4 pores along 

 the forehead and snout; in the suborbital branch (tig. 

 2")3, sob — poh) 9 oi' 10 in a row sui'rounding the lower 

 ])art of the eye and advancing along tiie snout to a 

 ])oint just in front of the nostrils; in the niandil)ular 

 branch 5 |)ores on the under sui'face of the lower jaw 

 (de) and H at the preoperculai' margin. The occiput 

 is crossed on each side by a serjjentine groove (the 

 supraorbital l)rancli, cf. above, fig. 104, p. 368), ending 

 at the outer extremity in a similar pore, from which 

 a, row containing 8 (n- 4 pores runs back, along the 

 temple, to the ujjper angle of the gill-o]iening. The 

 body is covered witli soft, middle-sized, and imbi-it'ated 

 scales (fig. 254), each enclosed in a thin follicle and 

 naked only at the tip, which apj)ears in a small, an- 



of the length of the abdomen, measured from the- an- 

 terior (lowei') end of the shoulder-girdle. 



Among the seven fins the vertical, \\hich are si- 

 tuated on the tail, are most developed, forming the 

 ])rope]ler by the aid of which the Pike darts like an 

 arrow on its prey. The dorsal fin is high and rounded. 

 It begins vertically aliove the vent, at a distance from 

 the tip of tiic snout measuring 67 — 69 ■%; of the length 

 of the body, and terminates al)ove the end of the anal 

 fin. Its base measures about 11' , — 13''2 9//, and its 

 longest ray about lO^^ — ll'/j *% of the length of the 

 body. The anal fin is similar to the dorsal, but shorter, 

 usually almost as high as it is l<.)ng. Its distance from 

 the tip of the snout is about 71 — 74 ?»', its base about 

 10'/,— 9', 2 %, and its height aliout 10—11 %, of the 

 length of the body. The caudal fin is slightly forked. 

 The middle rays, which occupy about 6 — 7 % of the 



Fig. 254. Scales of the Pike. X 2. A. from Uie anlcTior part of tlie body, above the lateral line; B, from the lateral line; 



C, from the ventral side. 



gular opening, usually of a distinctive colour. In shape 

 they are rounded and oblong, or (on the belly) more or 

 less pointed behind; and they are most distinguished 

 by the cleavage of the anterior (inserted) jjart into three 

 or four lobes. The lateral line is straight, and runs 

 somewhat nearer to tlie back than to the bell}'. It is 

 marked by scales incised at the tip, but is interrupted 

 here and there by scales with entire ti]). ( )n each side 

 of the lateral line, especially on the tail, there are 

 scale-rows similar in the structure of the scales to the 

 lateral line, but varying in number, extent, and position. 

 At the outer angles of the ventral fins the usual scale- 

 fiap" is wanting. 



Tile anal aperture, which is large, lies so near to 

 the caudal fin that its distance therefrom is only '3 



length of the body, are about half as long as the long- 

 est ra3's in the fin. 



The pectoral fins are oljliipiely rounded and set low. 

 Their length in adult Pike is about 10 — 13 % of that 

 of the body. The ventral fins ai-e of about the same 

 size. They are situated half-way along the body, and 

 the preabdominal length is about ^^ (in gravid females 

 as much as ^\„), the postabdorainal about ' , (in gravid 

 females somewhat more), of the length of the body. 

 Without any examination of the internal organs, the sex 

 may be determined by the fins, which are generally larger 

 and more rounded, with thicker rays, in the male than 

 in the fenaale. The length of the pectoral fins, in parti- 

 cular, is somewhat more in the male, less in the fe- 

 male, than half of the preabdominal length. 



" Cf. above, on the Loaches (ji. 709 and note d) and on the Minnow (p. 751)). 



*■ In the fry abont 36 — 38 %, in Pike i — 5 dm. long about 44 — 47 %, of the length of the head. 



' In the fry about 34 — 38 %, in Pike 4 — 5 dm. long about 38 — 43 %^ of tlie length of the head. 



'' In the fry about -/ai in tlie males commonh' less than in the females. 



