318 THE FRESII-WATKi; FISHES OF EUROFE. 



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

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

 rated, in which the numbers are 2:20, 200, 195 to 200, 190, 180, 170, 1G5, 

 and 1()0. Some of the species found in other localities fill in i^aps in this 

 oradation. Sulii/.o hue ho, however, may be considered a distinct species, since 

 it differs from the ordinary Charr in havint]^ no median teeth on the hyoid 

 bone, a character in which it resembles the Saliiio foniinalis of the northern 

 ])arts 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 thoug-h they were species in process of 

 development, still showing their connection with the parent stock. 



Salmo salvelinus (Linnaeus). 



D. 12—1.3, A. 13, P. 13, V. 9, C. 17/0— 7. Sq. lat. 220. 



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

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

 scarcely so elongated as the ILucli ; jjut the proportions vary considerably 



% 



Fio-. 161. — SALMO SALVKLINTS (LIXN-lCrs). 



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. IJsuall}^, 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 e(]ual to each other. 

 The head is live and a hall' to six times as long as the eye. The eye is less 



