■2H XAKKATIVE OF THE EXPEDITION OF 1896. 



first boring, were numerous reefs, from Avhich we obtained many living corals, mostly 

 of sijnilar species to those growing in the outer sea, and though the upper surfaces of 

 these reefs exposed at low tide were dead, their sides were completely covered with 

 living forms, a fact to which I can bear most positive witness, since I have swum 

 I'ound them for a considerable distance at a depth of 4 or 5 feet under water, a feat 

 to which I was frequently tempted by the extreme beauty of the spectacle afforded 

 by the exquisite and vivid tints of the extended coral polyps. 



The calcareous algae are chiefly represented Ijy Halimeda, which was brought up by 

 most of the soundings, and sometimes filled the net used for dredging. During 

 the whole of one afternoon which I spent with the sounding party under Mr. Payne, 

 the boatswain, I noticed Halimeda adherent to the armature of the lead nearly every 

 time it was brought up. Foraminifera abound, and constitute the larger part of the 

 sand of the lagoon mounds. The sand in the " neck " (Te Ava uni uni) of the atoll 

 is chiefly composed of them, as also is that of the sandy beaches, which extend for 

 100 yards or so into the lagoon. The growth of these organisms would appear 

 to be rapid, for the natives informed us, and Mr. O'Beien, the white trader, confirmed 

 their statement, that twenty yeai'S ago the lagoon opposite the Mission House was 

 14 or 15 feet deep, where now it is filled up witb sand nearly to the level of the 

 beach. Evidence of a similar rapid filling up of tlie lagoon of Nuku lai lai was 

 given by Collins, the white trader on that atoll. 



The sand of the beach is constantly shifting under the action of the winds. Pava 

 and Fualifeke, shown as separate islets on the chart, are said to be joined together 

 after the prevalence of westerly winds, which sweep the sand to tlie north and south, 

 while easterly winds drive it on to Fualopa. The spot on which our " fale," or native 

 house, stood is sometimes buried mider sand by a westerly gale. Notwithstanding 

 the large contribution of organic sand which tlie lagoon is periodically making to the 

 land, it is itself, as we have seen, becoming levelled up in places by fresh accessions 

 of this material. 



Note. 

 Samj)les of water were collected from the lagoon at different depths for 

 chemical examination. Their analysis was most kindly undertaken by Pi'ofessor 

 J. Emerson Reynolds, F.KS. The results, for the samples collected in lat. 

 8° 26' 36" S., long. 178° bb' 22" E., are as follows :— 



Cliloi'ino per litre. 



Siu-fcice 19-60 



Depth of one fathom 19'24: 



Depth of 30 fathoms 19-66 



The COg radical Avas determined in terms of COo, and proved to be : — 



Carbon dioxide per 

 litre. 



Surface 0-132 



One fathom 0-132 



30 fathoms 0-132 



