318 THE FRESH-WATER FISHES OF EUROPE. 



is cumulative in the direction of increased size of the scales, as expressed 

 by their diminished numbers in the lateral line, in the several forms enume- 

 rated, in which the numbers are 220, 200, 195 to 200, 190, 180, 170, 105, 

 and 160. Some of the species found in other localities fill in gaps in this 

 gradation. Sal mo huclio, however, may be considered a distinct species, since 

 it differs from the ordinary Charr in having no median teeth on the hyoid 

 bone, a character in which it resembles the Salmo fontinalis of the northern 

 parts of North America, a fish which has recently been successfully intro- 

 duced into British lakes and rivers. 



But while we advocate the institution of larger species for closely-allied 

 fishes, it seems indispensable that the constituent varieties of those species 

 should be kept distinct, and treated as though they were species in process of 

 development, still showing their connection with the parent stock. 



Salmo salvelinus (LINNAEUS). 



D. 1213, A. 13, P. 13, V. 9, C. G/17/G 7. Sq. lat. 220. 



The Alpine lakes of Austria and Bavaria yield a fish which is known in 

 those countries as the Salbling. It has an elongated form of body, though 

 scarcely so elongated as the Hitch ; but the proportions vary considerably 



Fig. 161. SALMO SALVELINTJS (LINNAEUS). 



with sex, age, and localities, so that the species exhibits a multitude of 

 varieties. The young have a very short snout. The length of the head is 

 sometimes one-sixth of the length, and sometimes the fish is only four and a 

 half times as long as the head ; hence the height of the body may equal the 

 length of the head, or be greater or less. Usually, the height of the head is 

 two-thirds of its length, and its thickness half the head-length. The greatest 

 height of the body and its thickness are always nearly equal to each other. 

 The head is five and a half to six times as long as the eye. The eye is less 



