' LEUCISCUS MUTICELLUS. 173 



horizontal than in other species ; it does not quite reach back to a vertical 

 ine drawn from the front of the orbit. 



The dorsal fin begins half way down the length of the fish, and in specimens 

 from the Neckar is over the insertion of the ventrals. Its base is only half the 

 length of the head; and it is higher than long. Its first jointed ray is the 

 largest, and it is twice as long as the last ray. The anal fin has the shortest 

 rays, but its first jointed ray is similarly the longest, and twice as long as the 

 shortest. The pectoral fin is small, but its length exceeds that of the ventral 

 and the dorsal fins. The ventral fins do not extend back to the vent. The caudal 

 fin is deeply forked ; its longest rays are as long as the head. The number of 

 scales is remarkably variable in different localities. There are from forty-eight 

 to forty-nine scales in the longitudinal rows in the variety from the Danube 

 which Heckel distinguished as L. agassizii, and fifty-six scales in the lateral 

 line in the variety which he named L. rysela. Giinther found in specimens 

 from the Neckar that the number varied from fifty-four to sixty. The 

 middle scales are about the size of a pupil of the eye, though some scales are 

 large enough to cover the yellow ring round the pupil. The free margin of 

 the scale shows a fan of eight to ten rays. The scale is as high as long. The 

 lateral line is yellow. 



The colour of the back is dark grey, varying into steel-blue ; the abdomen 

 is of shining silver. A black, longitudinal band, which often commences at 

 the tip of the nose, goes through the eye and over the operculum to the tail. 

 It is formed of densely-grouped black pigment spots. At the fore part of the 

 body it has the width of three scales ; behind the anal fin the width is reduced 

 to one scale and a half; but the band widens again, so that at the base of the 

 caudal it is nearly five scales wide. 



All the fins are transparent and unspotted in Austrian specimens, but in 

 examples from the Neckar the fins of the lower part of the body are yellow 

 at the base, and this colour is occasionally seen in the dorsal and caudal. 

 Bavarian fish have much black pigment in spots on the dorsal and caudal fins. 

 In the tributaries of the Danube the largest specimens have a length of about 

 five inches ; but the fish is larger in the Neckar, Dr. Giinther obtaining 

 specimens nine inches long at Heilbronn and it is equally large in Bavaria. 



The pharyngeal teeth have a compressed form, are hooked, and slightly 

 denticulated (Fig. 96). 



This fish feeds on animal and vegetable substances, and Giinther found 

 small molluscs and beetles in the stomach. The lining membrane of the 

 visceral cavity is black. The number of thoracic vertebrae is twenty to 

 twenty-one, and of caudal vertebrae nineteen to twenty-one. There are sixteen 

 to eighteen pairs of ribs. 



