450 NATURAL SCIENCE. august. 



After towing for, say, twenty minutes, the net is again brought to the 

 vertical, and the messenger sent down to close it ; after which, it is 

 brought up to the surface, and the contents of the upper and lower 

 portions of the net examined separately. 



This net was used on several occasions in water of considerable 

 depth, and undoubtedly failed to produce evidence of a mid-water 

 fauna of any variety or abundance. The number of unexceptionable 

 trials at depths of 400 fathoms and upwards was, however, too small 

 to justify any far-reaching conclusions. 



The Galapagos Islands occupy the next section of the Report. 

 This group consists of some nine or ten moderate-sized islands with 

 several small ones. With the exception of a small colony maintained 

 on Chatham Island, they are, as when first discovered, uninhabited. 

 Their vegetation presents three distinct belts or zones. The first, in 

 close proximity to the shore, is characterised by stunted salt-loving 

 plants ; among them are a Verbena and an Acacia with small leaves 

 and inconspicuous flowers, and a large tree, the Palo Santo. Where 

 the lava prevents the growth of anything else, we still have an 

 Opuntia and a Cereus. As we ascend the latter disappears, as also 

 the Verbena, while the other two increase in size. The second belt 

 is found where the lava has become decomposed into soft reddish 

 earth, on which grow woods of small trees resembling the Andean 

 Polykpis. From this there is a gradual passage to the third region, 

 which is bare of trees and covered with coarse grass. The bulk of 

 the vegetation seems to have been derived, as might be expected,, 

 from Central America. The amount of decaying vegetable matter 

 brought up by the trawl has already been alluded to, and, as Mr. 

 Agassiz remarks, " certainly offers a very practical object-lesson 

 regarding the manner in which " these islands must have received 

 their vegetable products. Autotype reproductions of a number of 

 photographs taken on the expedition show very clearly the general 

 features of the vegetation. 



The land fauna does not seem to be abundant : the giant 

 tortoises, once so numerous that single vessels have been known to 

 carry off seven hundred at once, have now disappeared. The only 

 tortoise obtained by the " Albatross " was got on Duncan Island : it 

 was sent alive to Washington. A bat is known, but appears to have 

 been on these islands only for the last six or seven years. The 

 insects are not numerous ; caterpillars were very abundant, but only 

 of few species. Quite a remarkable number of domestic animals 

 have now become feral. 



A great deal of coral rock, in isolated patches, is found about 

 these islands, and the so-called " sandstone " proved, on examination, 

 to be a slightly oolitic coral rock. There are, however, no true reefs 

 either on these islands or anywhere in the Panamaic region. 



The author discusses the recently expressed views of Dr. Baur 

 on the origin of the Galapagos Islands, and comes to the conclusion that 



