AFFINITIES OF GALAPAGOS SNAILS 
809 
their distribution to be of much service in this study, but 
Dr. Gunther records a woodlouse (Cubaris galapagoensis), 
which is apparently related to a West Indian form. The genus 
Cubaris, which is otherwise confined to the West Indies, 
Florida, Central America, California and South America, is 
the American representative of Armadillo. The latter has its 
headquarters in southern Europe. Cubaris, no doubt, owes its 
presence in America to the fact that some ancestor common 
to it and the European Armadillo crossed over by the trans- 
Atlantic land bridge described in the last chapter. 
On the whole, remarks Dr. Wallace,* the flora agrees with 
the fauna as indicating a moderately remote origin, great 
isolation, and changes of conditions affording facilities for 
the introduction of organisms from various parts of the 
American coast, and even from the West Indian islands and 
the Gulf of Mexico. As in the case of the birds, he continues, 
the several islands differ considerably in their native plants, 
many species being limited to one or two islands only, while 
others extend to several. 
A point of great importance in connection with the theory 
of dispersal of seeds by marine currents is the condition of 
the coasts of the Galapagos islands. The dried up desert 
aspect of the islands on landing has been commented upon by 
Darwin. Dr. Wolf f gives us his impression of the same 
islands during the rainy season. The lower zone up to six 
hundred feet is only very sparsely covered by vegetation. The 
whole landscape has a greyish-brown appearance. A Lantana, 
a couple of Crotons and a few Euphorbiaceae and Compositae 
are the principal members of this wretched flora. The only 
plants that thrive in this district are two giant Cactuses, 
reaching to a height of about twenty feet. They seem to 
select the driest and roughest spots, where nothing else will 
grow. Herbaceous plants are restricted in this lower zone 
to a few parched grasses and a few shrivelled diminutive 
plants. There are very large districts, moreover, where 
nothing whatsoever will grow, the ground being paved, as it 
were, with enormous blocks of lava. At a height of about 
* Wallace, A. II., “ Island Life,” p. 2S9. 
f Wolf, Th., “ Die Galapagos Inseln,” pp. 257—260. 
