204^ THE FKESH-WATEK FISHES OF EUROPE. 



The cleft of the mouth is always more arched than in Ch. nasns. The 

 pharyngeal bones usually have a shallow notch on the front part of their 

 external margin; and the pharyngeal teeth are generally 5 — Q, or 5 — 5; but 

 there is sometimes an additional tooth in a separate series. The nose pro- 

 jects but slightly over the mouth, is blunt and rounded. The fish closely 

 resembles Ch. (jenei in the fins, snout, and mouth ; but the body is less elon- 

 gated. There are five scales between the extremity of the pectoral fin and the 

 ventral. This type most resembles Leuciscus muticellus in colour, being slaty- 

 grey on the back, silvery -white on the sides, and white below. A band formed 

 of spots of black pigment, giving a grey effect, runs from the head to the tail, 

 but is sometimes wanting. The fins are orange, but the dorsal and caudal are 

 margined with black, and there is a similar but fainter border to the pectoral. 

 Sometimes the angle of the mouth and operculum are orange. The length of 

 this fish varies from eight to fourteen inches. It is very rare, and has been 

 found in Bavaria, in the rivers Inn and Isar, and is stated to occur in the 

 Danube, and in the Rhine at Basel. It has no distinctive provincial name. 



Chondrostoma polylepis (Steindachner). 



13 

 D. 11, A. 12. Scales : lat. line 68 — 75, transverse — 



9. 



This fish, when taken from the clear mountain waters of Spain, is darkish- 

 green on the back, with a wonderful metallic glimmer, and is golden on the belly. 

 The fins, except for their black margins, are reddish. The head is covered 

 with blackish -bi-own flecks, and there is a blackish fleck on every scale. 

 Specimens from the Tagus and the rivers flowing in the low-lying country 

 are much paler, olive-green, or brownish in colour, and there are only 

 fine black points on the body scales. At the uj)per part of the body 

 the scales are darker at their edges than in its middle. The fish reaches a 

 length of sixteen inches, but is rarely more than ten inches long in the fish 

 markets of Toledo and Madrid. It is popularly known in tlie Spanish penin- 

 sula as Bixja, and also as Madrilla. 



The form of body is elongated. The greatest height in front of the 

 dorsal fin, in yoving individuals, is equal to the length of the head, while in old 

 individuals the head is relatively shorter. The fish is five and a half times as 

 long as the head in the young, while in the adult the head is one-sixth of the 

 length. It is more than twice as long as wide. The eye varies, becoming 

 relatively smaller with age, and is between one-fifth and one-sixth of the 

 length of the head in the adult. The snout is arched and broad, and is pro- 

 longed in advance of the transversely horizontal mouth, the angle of which 



