LEUCTSCUS ERYTHROPHTHALMUS. 135 



young fish, or sometimes more, while it is less than one-fifth of the length of 

 the head in the adult. The forehead widens with age ; the dorsal fin is nearer 

 to the caudal than to the snout, higher than wide, with its longest ray as long 

 as the head. The vent is in a line behind the end of the dorsal and imme- 

 diately in front of the anal fin. In the male fish the pectoral fins reach to 

 the base of the ventrals ; the ventrals 

 are equally long, but do not reach to 

 the vent. All the fins have the rays 

 rather longer in the males than in the 

 females. The latter, on the other hand, 

 have the bases of the anal and dorsal 



fins relatively elongated. Fig. 62 shows 

 . ;i r i , ,1 Fisr. 62. PHARYNGEAL TEETH OP LEUCISCUS 



the pharyngeal teeth. ERYTHROPHTHALMVS. 



The scales are strong, firmly adherent, 



and overlap each other considerably ; they are longer than wide, rounded at 

 their free border, and more truncate behind. There is a central knot, from 

 which three or more furrows or canals radiate, and between these there are 

 usually several indistinct furrows. Hence the concentric lines of growth are 

 sinuous, and the free border of the scale is slightly undulating. The largest 

 scales are in the lateral line, and exceed the diameter of the eye. The number 

 of scales in the lateral line varies from thirty-nine to forty-two. According 

 to Dr. Giinther, there are seven and a half scales above the lateral line and 

 five and a half below, and, according to Heckel and Kner, four rows above 

 and three below. 



In clear running water the back of the fish has the shining aspect of 

 polished steel, with blackish smears; the sides are brassy-yellow, the belly 

 silvery, the anal and ventral fins, and more rarely the dorsal, are blood-red ; 

 the bases of the caudal and dorsal are usually black ; the caudal is red at its 

 extremities, but the bases of the anal and ventral fins are white ; the pectoral 

 fins are nearly colourless, though sometimes tipped with red. The iris is 

 orange- yellow, with red flecks. The young are paler-coloured; in the first year 

 their fins become red at the margins, and it is not till the end of the second 

 year that the full coloration of the mature fish is acquired. The colours, 

 however, vary with the locality, and differences have been which characterise 

 the fish in different parts of Europe. Dr. Day mentions that when taken 

 from deep water the colours are similar to those of Roach or Dace. 



A variety with black fins, especially the ventral and anal, is found in 

 the lakes of Northern Italy, in the ditches of the rice-fields, and in the Enga- 

 dine. It is known to the Italians as the Devil's Fish (Pesce del Diavolo) ; 

 and as Scardola in some localities, and Piotta in others. 



