. 670 The American Naturalist. [August, 
to have directed attention to the discussion here. It is worth 
adding, however, that Baur’s article is supplemented by an ex- 
cellent bibliography.” 
On October 24, 1895, Hemsley” published a review of Rob- 
inson’s and Greenman’s Flora of the Galapagos Islands. 
“ Dr. G. Baur’s theory of the origin of the Galapagos Islands 
is too well known to need explanation here; yet, it may be 
briefly designated the theory of subsidence. He argues that 
the islands were formerly connected with each other, and at 
an earlier period with the American continent. It is also al- 
most needless to say that this theory has met with an exceed- 
_ ingly hostile recognition. The publication of an account of 
the botanical collections (Robinson and Greenman) affords an 
opportunity of examining this theory from a botanical stand- 
point. For the purposes of the ‘Botany’ of the Challenger 
Expedition, and ever since that publication of this work, I 
have collected all the data coming under my notice bearing 
on the dispersal of plants to considerable distances by wind, 
water, birds or other creatures, excepting human. The evi- 
dence thus collected sufficiently accounts for the vegetation of 
low coral islands, and the littoral vegetation of widely separated 
countries ; but it in no way helps to explain the vegetation of 
the enormously distant islands of the Anarctic seas, for exam- 
ple, or that of the islands of the Galápagos group, to give an- 
other instance. 
“ But these are not parallel cases; they are the two extremes 
in the amount of differentiation in connection with isolation. 
“ The biological phenomena of the Galapagos Islands left a 
deeper impression, probably, on the mind of Darwin than those 
of any other part of the world he visited, and doubtless had 
the theory of subsidence, and I found that it did not. Professor Agassiz did not 
refer with one word to this harmony of distribution, which formed the basis of ™Y 
whole ideas. When Professor Agassiz, or any one else, is able to explain this by | 
the elevation theory, I shall be the first one to adopt it. But, until this has been 
done, I believe in subsidence. The paper to which Professor Agassiz refers Ws 
written before my visit to the islands. My investigations have only more con 
vinced me of the insufficiency of the elevation theory.”’ 
Hemsley, W. Botting. The Flora of the Galápagos Islands. Nature, Vol. 
52, No. 1356, October 24, 1895, p. 623. 
