492 SMITHSONIAN MISCELLANEOUS COLLECTIONS [voL. 48 
conclusion is, that if the terrestrial fauna can be shown to have come 
that way, the plants fully sustain the whole theory of a land bridge. 
The plants in that case more particularly prove the direction whence 
came the invasion, while the animals demonstrate, in addition, that 
there must have been a land bridge in that direction. 
Not all terrestrial animals,’ however, are equally suitable to prove 
such connection. Obviously, birds are of less use than plants. 
Their general distribution, such as that of the ptarmigan, the twite, 
and the rock pipit, may show the direction whence they came, but 
even the ptarmigan would be able to cross the Norwegian channel, 
though it is very doubtful if it could cross the North Sea at the 
present level of the sea. I am, therefore, not going into detail | 
here about cases such as those of the west Norway wren (Anorthura 
bergensis) and the chickadee (Parus colletti) although they fit 
very well into the general scheme. I have on another occasion 
(Smituson. Misc. CoLx. (Quart.), XLVII, 1905, pp. 428-429) called 
attention to the case of the dipper (Cimclus), and shall here only 
mention Columba livia, the rock pigeon, as another bird which prob- 
ably reached west Norway from Scotland. 
The insects also will have to be left out of consideration, though 
it should be mentioned that an element of the west Norwegian insect 
*The present essay deals only with the terrestrial biota, but if a Scoto- 
Norwegian land bridge ever existed, as here suggested, a littoral fauna and 
flora must have accompanied the dispersal of the terrestrial one. To prove 
in detail the existence of such a littoral assemblage would add a very im- 
portant link to the chain of evidence, but various reasons prevent its elabora- 
tion by me. The case of a characteristic littoral fish may serve as an 
example in this connection, however. 
The Blennius (Lipophrys) pholis, or shanny, is one of the most character- 
istic beach animals. According to Day (Fish. Great Brit. Irel., 1, 1884, p. 204) 
it “is found in rock pools accessible at low water and does not appear to 
frequent deeper localities.” Smitt (Scand. Fishes, 2d ed., 1, 1892, p. 216) 
says that it “prefers to live above low-water mark and seems... to find 
pleasure in being left dry at ebb-tide.” The female deposits its eggs in “a 
small hole with a narrow entrance just above low-water mark.” Its geograph- 
ical distribution is characteristically “Atlantic.” “Its true home is on the 
coasts of Great Britain and Ireland, extending southward... into the 
Mediterranean at least as far as Barcelona” (Smitt, p. 217). According to 
Day (p. 205) it “appears to be distributed almost everywhere in pools be- 
tween tide marks around the British coast....In Ireland it is common.” 
It is not found in Denmark or Sweden, but in Norway it occurs on the 
west coast from Stavanger northward at least up to Manger, a little north of 
Bergen. : 
