208 SPECIES IN OUR SALMONIDAE 



less in the differentiation of forms, the same is 

 found to be the case in the examination of 

 structural characteristics. A full statement of 

 the results arrived at, after careful examination 

 of all the varied points of difference that have 

 been held to constitute valid evidence of specific 

 distinction, will be found in Dr. Day's British 

 and Irish Salmonidae, where it is shown con- 

 clusively that in each and every case such 

 characteristics have been found to be incon- 

 stant when the examination extended over a 

 sufficiently large number of examples. All these 

 forms or races agree in 'essential character- 

 istics.' 



It has also been proved by careful and re- 

 peated experiment, notably by Sir James Mait- 

 land and Dr. Day at Howietoun, that the various 

 forms, both anadromous and fresh water, are 

 capable of breeding inter se, and that their pro- 

 geny are fertile. It has further been established 

 there that the descendants of an anadromous 

 race, artificially reared and confined to fresh 

 water, have themselves reproduced their kind. 

 In November, 1885, Dr. Day exhibited at a 

 meeting of the Linnean Society a par 5^ inches 

 in length, one of a shoal hatched at Howietoun 

 in March, 1885, from parents themselves reared 

 from ova and milt taken by Sir James Maitland 



