Vol. 62.] HALIMEDA AS A BEEF-FORMING- ORGANISM. 705 



In all the samples of material from the lagoon-boring at Funafuti, 

 as Miss Barton states, 1 



' The Halimeda -joints consisted entirely of H. optmtia var. macropus. The 

 borings down to 132^- feet 2 were still sufficiently well preserved to show the 

 peripheral cells on decalcification, and at 151 feet the large central tubes were 

 still to be recognized ; but below that depth, though the form of the joints was 

 retained, there was no cell-substance after treatment with acid.' 



In the solid cores of the main boring and the two earlier borings 

 made by Prof. Sollas (1st Expedition) at Funafuti, Halimeda is 

 well represented, but only in one place is it so abundant as to form 

 the greater proportion of the rocks, as in our specimens from the 

 New Hebrides. 



Dr.* G. J. Hinde makes the following remarks on the genus 

 Halimed.a occurring in the borings at Funafuti 3 : — 



' Detached joints of this genus are present in all the borings ; in some portions, 

 as, for example, in the Lagoon-boring, for 60 feet below the lagoon-floor they 

 form the greater part of the rock, and between 652-600 feet in the main boring 

 they are the main constituents of the cores. As a rule, their structure is well 

 preserved, so that they are readily recognized in microscopic sections. The 

 specimens in the Lagoon-boring have been determined by Miss Barton (Mrs. 

 Gepp) to belong to H. opuntia, Lam. var. macropus, Askenasy. According to 

 Mr. Finckh, Halimeda is remarkably abundant, both on the present floor of the 

 lagoon and on the ocean-slopes of the reef at Funafuti.' 



Fiji and Tonga. 



As affording an interesting comparison with rocks formed under 

 much the same conditions as those of the New Hebrides, we here 

 place in a connected form the notes, given in a recent paper by- 

 Mr. R. L. Sherlock, of the occurrence of fossil Halimeda in the raised 

 reefs of Fiji and Tonga. 4 



Fiji Group. 



Mango. — 280 feet: Mr. Sherlock records Halimeda in a lime- 

 stone associated with Lithoihamnion. The other organisms were 

 almost obliterated exceptiDg a doubtful foraminifer, Gypsina(!). 



At 298 feet Halimeda was abundant, associated with Litho- 

 ihamnion. At 300 feet Halimeda Avas again found, associated with 

 Lithoihamnion and corals. 



Niue (Savage Island). — Between the Tonga and Fiji Groups. 

 Mr. Sherlock found Halimeda in all three terraces. 



At 53 feet it was abundant, associated with alcyonarian and 

 tunicate-spicules, and Lithoihamnion. At 70 feet it again occurred, 



1 Journ. Linn. Soc. London (Botany) vol. xxxiv (1900) p. 481. 



2 Measured from the level of low-water spring-tide, deducting 101 feet for 

 the depth of the water to the floor of the lagoon. 



3 ' The Atoll of Funafuti ' 1904. p. 331. 



4 ' The Foraminifera & other Organisms in the Baised Beefs of Fiji ' Bull. 

 Mus. Comp. Zool. vol. xxxviii (1903) Geol. Ser. vol. v. No. 8, pp. 349-65. 



