260 PROCEEDINGS OF THE AMERICAN ACADEMY. 
alike than either is to that of the intervening Indefatigable; Jervis 
lying near James has a greater common floral element with the more 
distant Charles; the florulae of the Seymour Islands have a greater 
number of plants in common with Charles, Chatham, and Albemarle than 
with Indefatigable, of which the Seymour Islands are merely a detached 
spur. Although a high percentage of ferns has been recorded on James, 
not a single representative of this group has thus far been found on the 
adjacent Indefatigable. The common floral element between Duncan 
and the relatively remote Chatham is greater than with any of the three 
large islands, James, Indefatigable, and Albemarle, which to a consider- 
able extent surround it. In fact, the only cases in which it appears that 
proximity between two islands has brought about any marked similarity 
on their floras are on the one hand Narborough and Albemarle, and 
on the other Gardner and Charles, and even in the former of these 
pairs, the likeness is by no means close, for not over 71 per cent of the 
plants of Narborough have been observed on Albemarle. 
These anomalies in the different florulae must find their explanation in 
peculiarities of climate and soil, together with an element of chance — 
arising partly from imperfect exploration, and partly from the accidents of 
seed-dispersal. Although they are not fully explained by the theory that 
these are islands of emergence casually seeded, they are much less in 
accord with the Baur theory of subsidence; for, were the florulae rem- 
nants of a common flora persisting upon islands separated by gradual 
subsidence, it is evident that those islands would possess the most floral 
similarity which were nearest together and divided by the shallowest 
channels, since these would have been separated from each other more 
recently than the remoter islands, which are cut off by a greater depth of 
ocean. As we find no such relation prevailing in the Galapagos Islands, 
but have observed just the reverse, namely, that the more distant islands, 
separated by relatively deep channels, often show greater floral similarity 
than the nearer ones, it is necessary to conclude that the botanical evi- 
dence, so far as it has yet been made out, is opposed rather than favorable 
to the subsidence theory. 
ADDENDA. 
Plants collected on the Galapagos Islands by Dr. Franz Steindachner 
of the Hassler Expedition. 
After the greater part of the present paper was in type, I received 
through the kindness of Dr. A. Zahlbruchner and Dr. A. Heimerl of 
