28 



SCANDINAVIAN FISHES. 



The Perch is a. tish of such common occurrence, 

 that there are probably i'ew persons who require to 

 consult a description in order to recognize it. Its body 

 is compressed, broadest anteriorh', and covered Avith 

 hard scales, not easy to detach, and rough on account 

 of the hooks, as tine as hair, which fringe their outer 

 edge and are directed upwards." Tlie head is fairly large,' 

 compressed and somewhat pointed: the eyes are of ave- 

 rage size,' the jaws of equal length, the nostrils large 

 with a double opening, the mouth also large, the jaws, 

 the vomer the palatine bones and the phai-yngeals co- 

 vered with teeth. The back, which is somewhat elevated 

 anteriorly, is furnished with two distinct fins. The lateral 

 line arched and nearer the back than the belly. The 

 first dorsal fin yello^vish gray -without spots, excepting 

 a black spot to\vards the termination (sometimes at the 

 beginning as \\'ell): it Ijegins just over the insertion 

 of the pectoral fins and ends in a line with tlie vent. 

 The second dorsal fin, the ground colour of which is the 

 same, begins close to the end of the first, and ends a 

 little behind the termination of the anal fin. 



The body is grayish yellow, darker towards the 

 back, and marked with grayish black, transverse bands, 

 generally six in number, the middle ones being branched 

 at the top and ending in a point at the bottom: the belly 

 is white. The colouring of the fish varies greatly ac- 

 cording to age and the season of the year, and is also 

 considerably aftected by the nature of the bottom and 

 the composition of the water it inhabits. The young 

 specimens are always lighter than the old, their colours 

 being dirtier and their coloration less distinct. During 

 the spawning season the colouring of the males is brighter 

 and more distinct, and becomes still more so in summer, 

 the season when the Perch collects in shoals. The spe- 

 cimens wlfich live neai' stony shores and in clear water, 

 are always of brighter colour tlian those which frec[uent 



places where the bottom is weedy and muddy, and 

 thus acquire a faint and sickly colour. In dark, but 

 clear water, such as we often see in forest lakes, the 

 colouring of the fish is always darker than usual, and 

 the inferior fins and the tail are bright i-ed. 



The saccate part of the intestinal canal, or the 

 stomach, is comparatively large. The intestinal canal 

 forms two curves and lias three pyloric appendages 

 attached a little below the stomach. The liver consists 

 of two lol)es, the left one being the larger. The gall- 

 bladder is yellow and clear. The male has two milt- 

 sacs, but the female only one roe-sac. The air-bladder 

 is large, and occupies a considerable part of the ab- 

 dominal cavitJ^ The kidneys are placed lengthwise 

 below the spinal column. The bladder is saccate. There 

 are 20 or 21 ribs on each side, and the vertebrae are 

 41 or 42 in number. 



The Perch is one of the most widely spread Scan- 

 dinavian fishes. It is found at Kilspisjarvi (lat. 50° N.) 

 in Torneil Lappmark, and occurs too in Norway, where 

 it is called in some places Tryfe/ One may therefore 

 assume that, south of the degree of latitude mentioned 

 above, it occurs more or less plentifully in all Swedish 

 waters. It does not disappear even in lakes that are 

 very considerably above the level of the sea. Though it 

 often occui's in shallow lakes ^vitll a weedy and muddy 

 bottom, it thrives best in deep and clear water where 

 the bottom is stony, and best of all where there is 

 some current. In the sea it occurs oftenest on the 

 landward side of the island-belt, and especially at spots 

 where a river falls into the sea and diminishes the 

 saltness of the water. However, it is also found, 

 though more seldom, Avithin the Baltic in the outer 

 part of the island-belt where the open sea be- 

 gins. It is believed that the Perch thrives best in 

 northern latitudes, since it there attains its largest 



" These hooks (spines) are not present in the newly-formed scales, which are cycloid (vid. Winther, Naturh. Tidskr. Kbhvn, 3 R., 

 8 B., pp. 28 etc., Plate XVI), but soon become ctenoid, as the margin develops into 1, 3, 5, etc. spines (though the number is not always 

 odd), which afterwards become dciitoid in substance, and from time to time during their growth become detached at the root, though they 

 are still united to the surface of the scale, which continues to grow beneath them. In this way they eventually become fixed to the hind 

 margin of the scale, though the fragments of their former roots remain, arranged in rows directed towards the central part of the scale and 

 indicating the place, where their development originally began. 



' In a specimen SG'/, mm. in length the length of the head is 30 % of the length of the body. Where the length of body is on 

 an average 207 mm., the length of the head has proved to be on an average 27.6 % of the lengtli of body, where the length of the body 

 is on an average 262 mm., 26.7 %, and where it is 308 mm., 27. .5 %. 



'■ Lengtli of the body on an average 210 mm., longitudinal diameter of the eyes on an average 17.2 % of the length of the head. 

 Length of the body on an average 275 mm., longitudinal diameter of the eyes on an average 15.5 % of the length of the head. Length of 

 the body on an average 308 mm., longitudinal diameter of the eyes on an average 14.3 % of the length of the head. 



'' Its range in Norway is confined, however, according to Collett, to the northern and southern (not the central) parts. "As is the 

 case with several of our fresh-water fishes, it chiefly (or perhaps exclusively) inhabits two extensive districts far apart from each other, na- 

 mely the inland parts in the east, south of Dovre, where it has immigrated from Sweden, and Finmark, where it has originally come 

 from tlie Tiorth-east". Coll., 1870, 1. c. 



