Gwyniads 3 1 



venture near the shore, and are rarely caught except with 

 a net ; are difficult to capture uninjured ; and, when taken, 

 yet more difficult to keep alive. They present considerable 

 variation in shape and colour, even locally depending, 

 perhaps, on season, sex, and age, and specimens from one 

 lake may therefore be expected to agree less closely with 

 their relatives from another. They differ, in fact, in much 

 the same way as trout and some other fish do ; and were a 

 large series of specimens, from different localities, available 

 for comparison, one variety would probably be found over- 

 lapping and running into another, just as is the case with 

 Salmofario and S. trutta. Under the circumstances it is not 

 therefore surprising that opinions should be divided as to 

 whether the genus Coregonus ought to be further sub- 

 divided, or whether some of those already regarded as 

 distinct might not with advantage be grouped together 

 as mere races, scarcely even entitled to sub-specific rank, 

 of one variable species. The latter is certainly the opinion 

 of the writer, so far as some of the British members of the 

 family are concerned ; and if, as seems not improbable, 

 the whole are but the land-locked descendants of one 

 originally migratory, or salt-water fish, then the wonder 

 becomes rather that such long isolation, and inter-breeding, 

 should have produced so slight a change than that the 

 individuals from one lake should differ somewhat from 

 those found in another. The geological formations of the 

 lakes in which the fish occur may possibly be sufficient, 

 in some cases, to suggest the possible period when particular 

 races may have been founded, and, if that be accepted, the 

 variation becomes relatively insignificant. How long it 

 takes for a race to develop into a species, or what, exactly, 

 the definition of a " species " ought to be, are always 

 interesting themes, and the history of the Gwyniad, could 

 we trace it, might shed much light on the matter. The 

 young individuals from Bala Lake are much slimmer, more 

 silvery, and altogether very different looking fish from larger 

 examples ; and as both large and small, or old and young, 

 appear to breed, it is curious (in view of the proverb that 

 " like begets like ") that a large and a small race have not 



