342 THE FRESH- WATER FISHES OF EUROPE. 



fin is less than one-fifth of the entire length, and the height always exceeds 

 the length of the head, which is one-sixth of the entire length of the fish. 

 The diameter of the somewhat large eye is one-fifth of the length of the head ; 

 it is separated by its own diameter from the snout ; and the width of the 

 frontal interspace between the eyes is one and a half times the orbital diameter. 

 There is a half-moon-shaped fatty border in front of the orbit, but it is smaller 

 than in most other Salmonidse. The nares are small and double, midway 

 between the eyes and snout. The snout is vertically truncate ; the mouth is 

 terminal and the broad upper jaw partly covers the mandible. The mouth is 

 toothless, but there are short pointed teeth on the tongue. The 'frontal profile 

 rises in a moderate curve, and the dorsal profile is highest at the beginning of the 

 dorsal fin. The ventral profile is a more flattened curve in its middle part. 



Fig. 165. COREGONL'S WAKTMANNI (BLOCH). 



The gill-openings are wide ; they open below in the middle of the throat, and 

 extend laterally as high as the middle of the eye. The rake-teeth of the ante- 

 rior gill-arch are long, finely notched, and crowded together, while those of the 

 fourth gill-arch are pointed and not more than ten in number. There are nine 

 branchiostegal rays. The pseudobranchiee are comb-like and well developed. 



The dorsal fin commences in front of the middle of the body. It is 

 truncated behind, the longest rays are two-thirds of the height of the body, 

 and the last ray is one-third of the length of the fifth and sixth. 



The anal fin is placed far back, and resembles the dorsal, but is only two- 

 thirds as high. It is opposite to the small and low adipose fin. The ventral 

 fins are below the hinder part of the dorsal, as long as the pectorals, and have 

 the free margin rounded. The pectoral fins are pointed behind; the caudal fin is 

 deeply forked, evenly lobed, longer than the head, with seven to eight short 

 truncated rays on each side of the tail. 



The scales are nearly circular, soft, finely marked with concentric stripes, 



