STEJNEGER] ANIMALS AND PLANTS OF NORWAY 495 
the supposed Scoto-Norwegian land bridge is, therefore, no proof 
against its former existence, but may only show that the land con- 
nections we are considering in this paper only lasted a comparatively 
short time.’ Most convincing evidence of this is furnished by the 
fact that while the characteristically ‘“ Atlantic ’’ species are found 
both in Ireland and west Norway, though more numerous in the 
former than in the latter, neither has more than two species of tail- 
less batrachians, viz., one frog and one toad, the frog belonging to 
the same species, Rana temporaria, the toad, however, to two 
distinct species, Bufo bufo, in west Norway, and Bufo calamita in 
southwest Ireland. Scotland and west Norway have also only two 
species in common, viz., Rana temporaria and Bufo bufo,and these 
might, therefore, have been suspected of having come to the latter 
country from the west, were it not that they are absent in the islands 
north of Scotland. The absence of Bufo bufo in Ireland is also 
against such an assumption, since it is probable that the connection 
between Ireland and Scotland was severed after the supposed con- 
nection between Scotland and west Norway had been broken. Both 
species, moreover, are widely distributed over the whole northern 
portion of the palearctic region from the Pacific to the Atlantic 
without any special western tendencies. Both probably entered 
Scandinavia from the south. West Norway is particularly poor in 
fresh-water fishes, the only land-locked species being the charr 
(Salvelinus alpinus), but as it frequents salt water in subarctic cli- 
mates it is useless for our purpose. 
These groups of animals failing us, we have to fall back upon 
the mammals as furnishing the second best test of a continuous land 
connection. Of course, if the terrestrial species which we have dis- 
cussed above (pp. 462-480) came to west Norway from the west, 
there must have been at least a very close approximation of the two 
land areas. The red deer is a good swimmer and is able to cross 
*That such a period, although “comparatively short,” may represent a 
quite respectable space of time will be seen from the following consideration: 
Brégger (Strandl. Beligg. Sydcest. Norge, 1905, p. 290), estimates the time 
which in southeastern Norway has lapsed since the maximum of the post- 
glacial submergence at 18,600 years. It is pretty certain that all the fresh- 
water fishes of eastern and southern Norway have immigrated since then 
into those parts of the country from southern Sweden. ‘The climatic condi- 
tions may not at first have been favorable, but during the last 10,000 to 
14,000 years they probably offered no obstacles. Nevertheless, not one of 
them has as yet reached the waters of west Norway. The much longer 
Scoto-Norwegian land bridge may, therefore, easily have lasted at least 
10,000 years without any fresh-water fishes having been able to cross it. 
