•49 



Till' avent.sre lenuftli of the 'IVhcIi in Sweden is 

 about -2 oi- .") dm. 'Ilie lar<;est specimen Ekstroji ever 

 saw was 4 7 cm. \o\tjS — alreadv an extraordinan' size 

 — but Nil.ssox iiad a s|K'cinicn neari\' .").") cm. in ien^tli. 

 According to Blaxcii.vud the tish attains at the aiic 

 of one year a weight of alxjut I:.'.') gm., at tlie ag(^ 

 of three vears alujut 1 — 1' ., kgm., at the age of six 

 or seven Aears :^ — 4 kgm. 'i'liis last weight is gener- 

 ally given, on IJuicii's autliority, as tiu; maximum 

 weight of the Tencii, and ac(^ording to the reports sent 

 in to the Swedisii Fislieries Committee of 1881 the 

 species attains in tlie District of .lOid^i'iping a weigiit 

 of 8 Swedish pounds (o'l-^ kgm-), but this statement 

 needs contirmation". According to Fatio 'Pencil 4 dm. 

 long weigh about 1 ' . kgm., and Tench .') dm. long 

 2'/'e kgm. 



Tlie body is thick, liut laterally compressed and 

 fairh' deep, the greatest depth, at the beginning of the 

 dorsal tin. being more tiian '/^ of the length''. The 

 depth is comparatively greatest, however, in the hind 

 part of the body, for the Tench is tiie oidv one of our 

 Cvprinoids in whicii the minimum de])th of the tail, at 

 least in adult specimens, is about 14 %' (13 '/j — 15\., %) 

 of the length of the body or 7^ (58— ti5 ?^) of the length 

 of the head''. The dorsal jirotile ascends only slightl}-, 

 but in a regular curve. The back is convex througii- 

 out its whole lengtii, flatter beiiind than in front of 

 the dorsal tin. The liellv, on the other h;ind, is Hatter 

 in front of than behind the ventral tins, but in the 

 males is sometimes concave in the me(lian line between 

 the ventral tins and the anal tin. 



The head, the length of which is about 22 — 24 % 

 of that of the body, is thick and somewhat compressed. 

 Its breadth is about e(pial to its vertical depth at the 

 anterior margin of the orbit. The forehead is broad 

 and evenly convex, and lies in a line ^vith the snout 

 and occiput. Its breadth is always somewhat (about 

 Vio) greater than the lengtii of the blunt snout, which 

 in adult specimens occupies about JmS % of the length 

 of the head. The inoutli is small, but turned sharply 

 upward; the lips are thick. The length of the barbel 

 at the corner of the mouth is usually less than half 



the diameter of tin; eyes. The length of the upjier 

 jaw is about ' ., (24 — 27 %) and that of tlu; lower jaw 

 about ' , (30—84 %) of the length of tlie iiead. The 

 lower jaw is alwavs somewhat shorter tiian tlu; sutui'c 

 between the suboiicrculum and tlie opermlum, which 

 suture is as a I'ule erpial in length to ll](' snout. Tlic 

 e\-es are small, but eotnparatively larger as usual in 

 young s])ccimens: during the growth of th(^ fish from 

 1.") to 40 cm. their longitudinal diainetei' (sliglitly greater 

 than flic vertical) \arics between about 1.") and 13 % 

 ol' the length of tlie head or 4(» and 34 % of that of 

 tlic snout. They are set aliout half-way between tlie 

 occi|iuf and the tip of the snout, and so high that tiie 

 line from the middle of the margin of the upper jaw 

 to the middle of the caudal tin touches the inferior 

 margin of the iris. The nasal cavities, which lie twice 

 as far from the tip of the snout as from the eyes, an; 

 furnished, here as in the preceding genera, each with 

 two closely adjoining nostrils. The anterior nostril is 

 the smaller and has a projecting dermal flap at the 

 hind margin. The gill-openings are fairly large, their 

 height being about eipial to the least depth of the tail. 

 The opercula are smooth, rounded at the margin, and 

 furnished with a broad rim, which extends from the 

 ujipcr angle of the gill-opening to the point where the 

 branchiostegal membrane is attached to the isthmus, at 

 a distance of half the diameter of the orbits from the 

 branchiostegal membrane of the other side. The three 

 rays in each branchiostegal membrane are bent, broad, 

 and strong. The gill-rakers are short and scattered, 

 numbering about 13 in the outer row on the iirst 

 bi-anchial arch, 16 on the outer margin of the jiiia- 

 ryngeals. The five, or sometimes only four (more usu- 

 ally five on one side, four on the other) pharyngeal 

 teeth (fig. 187) are more or less (the foremost tooth 

 least) transversely (behind and in front) compressed, 

 with simple masticatorj' surfaces, depressed in the trans- 

 verse median line, and with the upper inner corner 

 more or less (most in the hindmost tooth) hooked. Tlw 

 pharyngeal cartilage is reddish brown like horn, of a 

 pointed oval shape (triangular with rounded lateral 

 corners and arcuate anterior margin), and almost hooked 



" Yarrell tells us (from Daniel's Mural A'ports) of n Tpin-h 33 id. long ami 1 1 lbs. 9' 4 oz. in weight, wliicli had Ions lived 

 closely confined among some roots in a pond choked up uith mud. 



' In adult specimens about 27 — 31 % of the length of the Imdy. In young specimens about 7 cm. long this percentage is about 

 21, according to Casestrisi. 



' In young specimens, however, according to Kroyer, about 1 1 ' j °o. 



' In exceptional cases, however, these percentages may be found in the Crucian Carp and the Wliite Bream. 



