240 THE FKKSIi-WATKi; FISIIHS OF EUROPK. 



GENUS. Leucaspius 



Leucaspius is a genus which was regarded by Heckel and Kner as inter- 

 mediate between Leuciscus and Alburnus. Its chief claim to generic dis- 

 tinctness from Alburnus rests upon the incomplete development of the mucus- 

 canal forming the lateral line, which in the single species known, hardly 

 extends beyond the pectoral fin. The scales are distinctive in their ovate form, 

 and their freedom from diverging fan-like rays, though, as Benecke points 

 out, some faint indication of two or three rays may be detected. 



Behind the ventral fins the abdomen is compressed into an edge. The 

 dorsal fin is short, and has no spine, and is opposite to the space between the 

 ventrals and anal. The anal fin includes more than thirteen rays. The lower 

 jaw projects beyond the upper, and its thickened median termination is re- 

 ceived in a corresponding depression. The upper jaw is protractile. The 

 gill-rakers are short and slender. The pharyngeal teeth are compressed and 

 hooked, sometimes in one row, sometimes in two. This type is known only 

 from Central and South-eastern Europe. 



Leucaspius delineatus (HECKEL). 



D. 11, A. 1417, V. 910, P. 14, C. 19. 

 Scales: lat. line 48, transverse 15. 



Heckel and Kner referred this species (Figs. 136, 137) to two different 

 genera Leucaspius and Squalius, owing to variations in the pharyngeal teeth. 

 When these teeth are arranged in a simple row of five on each side, it found 

 a place in the genus Leucaspius, but when one of these teeth was displaced, 

 so as to form a second row, it was referred to the so-called genus Squalius. 

 This circumstance may be a caution against attaching too much importance to 

 the characters of the pharyngeal teeth. 



The head is one-fifth of the length of the fish ; its length is equal to the 

 greatest height of the body ; and the thickness of the fish is equal to half the 

 height. The eye is large, its diameter being about one-third of the length of 

 the head ; and it is separated from the snout and from the other eye by its 

 own diameter. The mouth is very oblique, and its angle reaches below the 

 anterior nares. The lower jaw resembles that of Alburnus and Aspius in the 

 thickening of its median portion in front; it slightly projects when the 

 mouth is closed. The sub-orbital ring is broad. The profile is nearly straight 



