In this case, when one guess is set against another, it seems to me that the hypothesis first suggested, rather than the other, lies in the line of least logical resistance. I think it better to adopt provisionally some theory not involving the existence of a South Pacific Antarctic Continent, to account for the distribution of _Galaxias_. For this view I may give five reasons:
1. There are many other cases of the sort equally remarkable and equally hard to explain. Among these is the presence of species of paddle-fish and shovel-nosed sturgeon,[31] types characteristic of the Mississippi Valley, in Central Asia. The presence of one and only one of the five or six American species of pike[32] in Europe; of one of the three species of mud-minnow in Austria,[33] the others being American. Still another curious case of distribution is that of the large pike-like trout of the genus _Hucho_, one species (_Hucho hucho_) inhabiting the Danube, the other (_Hucho blackistoni_) the rivers of northern Japan. Many such cases occur in different parts of the globe and at present admit of no plausible explanation.
2. The supposed continental extension should show permanent traces in greater similarity in the present fauna, both of rivers and of sea. The other fresh-water genera of the regions in question are different, and the marine fishes are more different than they could be if we imagine an ancient shore connection. If New Zealand and Patagonia were once united other genera than _Galaxias_ would be left to show it.
3. We know nothing of the power of _Galaxias_ to survive submergence in salt water, if carried in a marine current. As already noticed, I found young and old in abundance of the commonest of Japanese fresh-water fishes in the open sea, at a distance from any river. Thus far, this species, the hakone[34] dace, has not been recorded outside of Japan, but it might well be swept to Korea or China. Two fresh-water fishes of Japanese origin now inhabit the island of Tsushima in the Straits of Korea.
4. The fresh-water fishes of Polynesia show a remarkably wide distribution and are doubtless carried alive in currents. One river-goby[35] ranges from Tahiti to the Riu Kiu Islands. Another species,[36] originally perhaps from Brazil through Mexico, shows an equally broad distribution.