232 



to us so strongly the entomology of the mountain region of the Alps of 

 Europe. The genus Parnassius, otherwise quite peculiar to the moun- 

 tain region of Europe, was found here, and no less than twenty-four 

 species, representing at least twelve genera and ten families of Euro- 

 pean butterflies, had their representatives in closely allied species 

 found upon our west coast. 



Mr. C. J. Sprague asked whether this distinction of faunae held 

 equally weU upon our continent from east to west as from north to 

 south. 



Mr. Scudder replied that it did, as he had already pointed out in a 

 paper read to the Society upon the genus CoKas some months pre- 

 viously, and remarked that in the comparisons referred to between 

 Western America and Europe it was not simply the intimate connec- 

 tion of one and another species taken at random that we had to 

 account for, but also the much more significant fact of the close rela- 

 tionship of the faunas of the two distant countries as a whole, often- 

 times in direct antagonism to the character of the faunae of the 

 intervening areas. He alluded to the case just mentioned by Mr. 

 Agassiz, of the association of Parnassius with large numbers of Ly- 

 cenidfe, and no Teriades, which characterizes Western America 

 and Europe alike, quite the opposite of which is seen in Eastern 

 America. 



Prof. Rogers thought we ought not to lose sight of the fact that 

 there was a similar coincidence in the physical characteristics of the 

 countries. 



Mr. A. E. VerriH mentioned that the similarity between the ani- 

 mals of the two regions referred to was not confined to the land animals 

 only, but was exhibited also in their Polyps. He also stated that an 

 undescribed species of frog, found by himself on the Mingan Islands, 

 in the Gulf of St. Lawrence, had been found by Mr. Scudder in Her- 

 mit Lake, at the upper portion of the mountain region of the White 

 Mountains, and had not as yet been discovered elsewhere. The 

 Rocky Mountain Swallow (Hirundo lunifrons Say), which had been 

 instanced as a case of recent migration, being now found in consider- 

 able abundance on the Atlantic coast, had been found in Maine, as 

 he had recently learned, so long ago as 1810. 



Prof. Rogers suggested that by a subsidence of a portion of the 

 western continent, and an elevation of the land now lying submerged 

 between America and Europe, we might have once had a physical 

 continuity of coast, with aU these species, or their common progeni- 

 tors, extending aUke along its whole area, and that with the elevation 

 and subsidence of the land to its present condition the contrasted or 

 similar physical conditions gradually developed would cause the de- 



