140 KENDALL: NEW ENGLAND SALMONS. 



from other communities, such as are sufficient apparently to justify their classification 

 as separate species, or at the least as incipient species. Mr. Regan suggests that the first 

 step towards the formation of a new species is probably the formation of such a com- 

 munity, either with new habits or in a restricted environment, and not as has sometimes 

 been supposed, a change of structure.' 



Prior to Regan others have advanced similar theories regarding the char. But each, 

 like Mr. Regan, seems to think that whatever change took place in structure, habits, 

 physiology, etc., happened after being restricted to the lakes. This is not in accordance 

 with a view previously expressed in this memoir to the effect that the evolution was in 

 progress while the fish was an anadromous marine form. The final isolation in lakes 

 retarded evolution, and variation was reduced in proportion to the number of inter- 

 breeding individuals in the communitj^ 



From preceding quotations and discussions it has been seen that early ichthyologists, 

 but more particularly many anglers, who gave the question any serious consideration, 

 regarded the lake salmon as distinct from the sea salmon. As previously indicated, they 

 beheved that the lake salmon was derived directly from the sea salmon by the latter 

 being confined in inland waters by some natural phj^sical obstruction which prevented 

 its return to the sea after spawning, or that young were thus prevented from going to sea. 

 Later, others suggested that the fresh-water forms were unknown prior to the erection 

 of dams which confined the salmon in fresh water. These theories were quickly and easily 

 exploded by showing that the dams did not prevent the salmon from going to sea but 

 did effectually prevent their subsequent access to the lakes. 



Furthermore, the case of the Canadian ouananiche, with its always unobstructed 

 access to the sea, was a decisive argument against the physical obstruction ideas but not 

 an explanation of the permanent residence of the fish in fresh water. In explanation of 

 this point G. Brown Goode, and later Samuel Garman (1896) expressed their opinions 

 to the effect that the lake salmon was the typical salmon and the marine, anadromous 

 fish, only a sea-run form. In other words the process was reversed and the taxonomic 

 type — Salmo solar ■ — was supposed to have had its origin in a natural type of Salmo 

 normally residing in fresh water. The 'sea-run' salmon was not regarded as specifically 

 distinct from the fresh-water form although the 'sea-run' form apparently never reverted 

 to its lake habitat and habits. 



Opposed to the fresh-water origin of the sea salmon is the fact that the lake salmon 

 naturally occurred only in a relatively few, fairly deep, cool lakes out of many in which 

 they did not occur although these apparently afforded similar conditions. It would 

 hardly seem that the sea salmon could be merely sea-run forms, as the lake salmon 

 waters afforded only a Umited number of relatively small nurseries to jdeld such an 

 abundance of sea-run salmon, unless the sea-running habit had been acquired at an 

 earUer geological period when the fresh-water distribution of the sahnon had been much 

 greater but had been reduced in a later period. 



It seems impossible to accept the latter alternative owing to the ease with which in- 

 land waters, other than those at present naturally occupied by the lake salmon, are 



