34 



KNOWLEDGE & SCIENTIFIC NEWS. 



[Mar., 1904. 



to completeness until to-day, but it is now told 

 in a handsome monograph just issued by the Royal 

 Society, to which source we are indebted for our illustra- 

 tions. 



The configuration of the atoll is seen on reference to 

 the model (Fig. 2^, and its fanciful rescnblance to 



the shape of a human head (view from the compass 

 letter S) has not escaped notice. The longest continuous 

 stretch of reef is 16 miles in length, and the most elevated 

 point abo\'e high water, 16 feet; while the general depth 

 of the waters of the lagoon is about 20 fathoms. One 

 peculiar feature of the atoll is its submarine cliflf, re- 



Fig. 4.— Hurricane Beach. Fcnafuti. and li\ing "Liihothamnion " kecr. 



Professor Edgeworth David 



the whole atoll elevated 



enable the portions 



present a clift" face 



Fiz- 5.— A Cluster ol the alga " Halimeda.' 



garding which 

 remarks that were 

 140 fathoms, it would 

 above the sea-level to 

 300-600 feet in height. 



Although we speak of Funafuti as a coral 

 island, in its fauna corals are the accessory 

 rather than the essential reef-builders, and 

 of the latter none aie more abundant and 

 contributory to reef-rock than the calcareous 

 algae Litlwthamnioit and Halimeda. Indeed, a 

 classification of the chief reef-forming or- 

 ganisms assigns their relative importance 

 thus: — (i) Species of Lithothamiiion, (2) Hali- 

 meda, (3) Foramiiiifera, (4) Corah. And Mr. 

 Mnckh, in a biological chapter, tells us, fur- 

 ther, that a coral once established adds to 

 the coral island by its growth only in the 

 same way as a tree once established adds 

 by its growth to the extent of a forest. In 

 the living state and by itself it cannot form 

 a solid mass ; dead, however, its skeleton 

 supplies material which the Litlwthamnion and 

 Halimeda unite together with the remains of 

 other calcareous organisms to make reef-rock 

 — mounting thus " On stepping stones of their 

 dead selves to higher things." (Figs. 3, 4.) 



Some interesting e.xperimentswere conduc- 

 ted relative to the effect of exposure to the 



