7o(> 



SPAN DIN A VI AN KISUKS 



siJv detaclied 



;it tlic inferior extixMuity. It may 1)< 

 from its place. 



The hofh' is cox ered witli vi-vv thin, olilciiii;', ;ind 

 imliricated scales, which are deeijl}" inserted in tlie skin 

 and thus appear externally to be \ery small. One of 

 lhe larger scales above the lateral line in a Tench 4 

 dm. long is 9 ram. in length and .'> mm. in breadth, 

 hut onh- the hindmost '2 mm. i^roject out of the follicde. 

 Tiie nucleus lies far forward in the covei'ed part. A 

 great luimber of radiating grooves run from the nucleus 

 in all directions to the margin of the scale (the most 

 numerous and densest to the hind margin); and the 

 fine, numerous, concentric stri;e encircle the nucleus, 

 running parallel to the margin of the scale. The scales 

 and follicles are clothed with a fairly thick, soft, and 

 slimv epidermis. The lateral line Ijends down in front, 

 and the!i runs straight .along the body, aliout e(|uallj' 

 distant from the back and bell\\ It contains about 

 100 scales. Above the line there lie about 30 scales, 

 below it about 20, in an o]jlir{ue row from the be- 

 ginning of the dorsal tin. 



The iieight of the dorsal tin is greater than the 

 length of its l)ase: the former measures in adult spe- 

 cimens about 18 '» (17 — 1!) %) nnd the latter about 

 13'/, % (1-2— 15 %) of tiie length of the body. The 

 distance between this tin and the tip of the snout is 

 about 48 % (47 — 49 %) of the length of the body, or 

 about twice as long as the dorsal margin of the ped- 

 uncle of tiie tail (l)etween the doi'sal and caudal tins). 

 Its first four rays are simple; but the tirst ray is al- 

 ways so short that it does not even project above the 

 skin; the second ray is also short and in old specimens 

 ditticult of detection, the third about half as long as 

 the fourth, which is only slightly shorter than the se- 

 cond or third among the branched rays. These last 

 two rays are the longest in the fin. Sometimes, how- 

 ever, even the fourth ray may be branched; and simple 

 or branched, l)ut narrow rays may be inserted here 

 and there between the branched ra)-s, which are other- 

 wise as a rule 8 in number. 



The anal fin is of exactly the same structure as 

 the dorsal and of essentially the same form; liut its 

 base is still shorter in ]tro[>ortion to its height. The 

 latter measures about 14 "y (13 — 15',, ^) of the length 

 of the body, the formei' about 8 % (7 — 9 %) of the 

 same. The beginning of the rtn lies at a distance fi"om 

 the fi]) of the snout of about 63 % (60—64 %) of the 

 length of the bofly. The vent is usually separated 



from the beginning of the anal fin by a distance about 

 equal to the diameter of the eyes (a little more or less). 



The caudal tin is broad and slightly concave at 

 the end, almost truncate wlien expanded. The length 

 of its middle rays, measured from the point \vhere the 

 scales end, is about 14 % (IS'/s — r6\\ %), that of its 

 longest lateral rays about 16 % (18 — 15'/o %), of the 

 length of the body. 



The jjaii-ed tins are broad and obli(|uel\' oval. The 

 most distinct external differences between the sexes tind 

 expression in the dimensions of these tins. In young 

 Tench and in tiie males the ventral fins are longer than 

 the pectoral tins, in adult females shorter. Tlie length 

 of the pectoral tins is about 16' , % (16 — 18 %) of that 

 of the bod\-: the length of the ventral fins is in the 

 females less than 17 % (15 — 16 %), in the males moi-e 

 than 17 % (about 18 %) of the same. It is also a rule 

 that in the females the ventral tins, wiien laid back, do 

 not extend to the vent, while in the males their tips 

 reach beyond it. In the males too, the second ra)- in 

 these fins is verv thick and broad. The distance be- 

 tween the ventral fins and the tip of the snout is about 

 42 % (39' ,—44 ?s) of the length of the body, their 

 position being generally farther back in the females. 



The coloration of the Tench adapts itself to the 

 water in which the fish lives. In clear water the wliole 

 bod)' is 3'ellowish green on a golden ground, with tine, 

 golden dots at the tip of each scale. The top of the 

 head is darker tiiaii the l)ack, the latter in its turn 

 darker tiian the sides, whicli fade below into tiie whitish 

 yellow colour of the liellv. This last colour also ex- 

 tends to the lower parts of the head and of the gill- 

 covers. All the fins are light green. The iris is cop- 

 pery red. — ^^'llen the tisii has been so long out of the 

 water that life is extinct, the colour is entirely changed. 

 The body is no^v dai'k green. The back, and in parti- 

 cular the top of the head, are blackish green. The fine, 

 golden dots have vanished. The belly is yello\\-. The 

 fins are dark purplisii red or nearly black. These last 

 organs are also the first parts of the body to change 

 colour. ■ — When the Tench lives on a muddy bottom, 

 it presents the ap])earance siiown in oui' figure. When 

 it is found in tiie foi-est tarns, wiiere tiie water is ge- 

 nerallv very dark, tiie entire upper part of the body is 

 black, as thougii dipped in ink, only the belly being 

 somewhat lighter. A not uncommon variety is the (jolden 

 Tencii, of a spotted or plain orange colour. This form 

 is often kept in tish-jionds Itoth in Germany and England. 



