26 L. HILLIS- COLIN VAUX 



Atoll ill the Ellice Islands of the south Pacific for the purpose of boring 

 a deep hole to test Darwin's hypothesis on the origin of atolls. The 

 first hole had to be abandoned after about 25 m of drilling, but two long 

 cores were successfully taken, the deepest penetrating to 339 m. 



For the history of Halimeda this expedition and its results were 

 especially significant for three reasons. An analysis of the cores showed 

 not only that Halimeda segments were prominent, and hence that this 

 alga participated in reef building, but also that in these particular cores 

 this calcareous green alga, by the volume of sediment contributed, 

 appeared to be more important than corals (Finckh, 1904). This 

 activity will be discussed in Section IX. 



A collection of intact specimens of Halimeda from various sites in 

 the atoll was ako m.ade during the expedition, and was given to Miss 

 Ethel Sarel Barton, later Mrs Gepp, of the British Museum (Natural 

 History) to identify. This led to a paper on the Halimeda of Funafuti 

 (Barton, 1900), but of much greater significance was her realization of 

 the vast inconsistencies in the existing taxonomy of the genus and the 

 need for its serious revision. Askenasy's skilful work pointed the way, 

 and the opportunity soon arose. In 1900, Madame Weber-van Bosse 

 asked Barton to work on the large collection of Halimeda made during 

 the Siboga expedition led by her husband to the Dutch Indies in 1899 

 and 1900. Barton began an intensive study of the genus as then available 

 to her, which led to the important monograph of 1901. 



D. The taxonomy of Barton 



Barton's investigation was a careful one. She dissected specimens 

 and measured various characters. But, most importantly, she saw and 

 examined as much of the type material of the species then recognized 

 as she could obtain. Consequently, she was able to compare specimens 

 with authority. She examined a number of characteristics in the many 

 plants available, mostly East Indian, and concluded that the pattern 

 of medullary filament fusion at the node was the most consistent 

 character and the only one of significant taxonomic value. 



Barton established three patterns of nodal medullary filaments 

 (Table III, Types 1, 2, 3, respectively) as follows: 



all medullary filaments come together into a single unit, 

 often with conspicuous pits or pores between adjacent filaments, 

 and then separate ; 



the filaments fuse, in pairs, for a short distance and then 

 separate ; 



