AGASSIZ: LETTEKS TO THE HON. GEORGE M. BOWERS. 81 



of Easter Island where there are no coral reefs. The edge of the crater 

 of Rana Kao drops perpendicularly a height of nearly 1000 feet in less 

 than one-eighth of a mile horizontal distance ; and the eastern face of the 

 crater of Rana Roroka rises vertically about 800 feet above the plain of 

 Tangariki. 



It is interesting to note how poor is the flora of the Manga Reva 

 archipelago as compared with that of the more western volcanic islands 

 like the Marquesas and the Society Islands and some of the western 

 elevated Paumotus. In the Gambler Archipelago the forests are reduced 

 to a few patches extending along the small valleys of the slopes of the 

 volcanic spurs. I am informed that even in the thirties of the last cen- 

 tury, when the missionaries first landed at Manga Reva, the forest trees 

 while more numerous yet never attained the luxuriance of growth that 

 they attain in the Society and Maixjuesas Islands. At the present day, 

 with the exception of the forest patches just mentioned and a few trees 

 which have been introduced for cultivation, the islands of the group are in 

 great-part thickly covered with a species of cane closely resembling that 

 of our southern States. It grows to a height of nearly 10 feet. The 

 fauna of Manga Reva is also extremely poor. There are no mammals, 

 and, with the exception of a "sandpiper," no indigenous birds. Sea 

 birds are few in number, and in our trip in the eastern Pacific we rarely 

 had more than three or four birds accompanying us; often only one, and 

 frequently none were visible for days. There are a few lizards on the 

 islands, apparently the same species as those in the Society Islands. 



We left Port Rikitea for Acapulco on the 4th of February to anchor 

 off Aka Maru ; on the 5th we left our anchorage, sounded off the east 

 face of Manga Reva, and took photographs. 



On our way north from Manga Reva to Acapulco we did not begin to 

 trawl or tow until warned by the surface nets that the surface was becom- 

 ing richer in animal and vegetable life, and also by the surface tempera- 

 tures indicating that we had reached the southern edge of the cold 

 western equatorial current. A little north of 10° south latitude we 

 made our first haul and deep tow, and found a very rich pelagic surface 

 fauna down to the 300-fathom line ; recalling the pelagic fauna of the 

 eastern lines and fully as rich. On trawling we foimd, as we expected, 

 a very rich bottom fauna. 



Among the animals brought np in the trawl were some superb 

 Hyalonemas, siliceous Sponges, Benthodytes, and other deep-sea Holo- 

 thurians ; fine specimens of Fi-eyella, and some large Ophiurans. This 

 haul is interesting as showing that in the tract of a great current, with 



VOL. XLVI. — NO. 4 G 



