REPORT ON .MATERIALS FRO>[ THE B0RIN(4S AT FUNAFUTI ATOLL. ;U7 



larger and coiuinoneL- forms can be readily distiuguislied with a lens on the smootli 

 surfaces of the slit rock cores, hut to make out the characters of the smaller forms 

 microscopic sections are requisite. 



Mr. Chapman has determined 41 genera from the various borings, which are given 

 in the accompanying list. Of this number 35 have been met with in the Main Boring. 

 By far the larger numl)er of the ger.era are, however, by reason of their rare 

 occurrence and hmited distril)ution, of but sniall signilicance as rock formers, the 

 commoner and generally disti-ibuted forms l)e]ong to the following 7 genera, given in 

 the order of their relati\'e almndance ; .iuqjln'stn/in/i, Poh/finno., Ofbitoiifcs, Ilciero- 

 steg/na, Carpevifcrid, (rtjpsina, and Ca/carina. These genera are represented in all 

 the borings, and in the Main Boring they are present from near the surface to the 

 bottom, the cores in many parts being packed witli them ; they are usually cemented 

 by crystalline calcite or dolomite so as to form a hard compact rock. 



The most noticeable of the foraminifera in the l)orings is Foly/rem<( planum, 

 Carter, which grows in concentric layers, forming spreading and nodidar 

 encrustations over corals and other organisms. In general appearance and in its 

 mode of growth, this S]3ecies closely simidates Lit hoth amnion, and very frequentlv it 

 occurs in layers alternating with those of the alga in so intimate a manner that only 

 in microscopic sections can they be distinguished. To this close association and 

 resemblance may be due the fact that this remarkable foraminifer appears hitherto 

 to have been little noticed, and it has probably been mistaken for Lithothammon. It 

 is found in the core materials from all the borings, and more abundantly in the solid 

 cores of the Main Boring between the depths of 650 and 750 feet, where the nodules 

 formed by its growth round small corals, &c., reach a diameter of 40-50 milliras. 

 Mr. Chapman"^" has called attention to its occurrence as a recent form in the beach- 

 sand of the outer reef-slope, and on the floor of the lagoon at Funafuti. 



Two other foraminifera, Alveo/ina Boscii, Defr. sp. and CycIocIi/jX'us Carpenteri, 

 Brady, may here be mentioned, since though conspicuous as regards their size, they 

 appear to have a restricted distribution in the Main Boring. AlveoUna Boscii was 

 observed, but not fidly identified, at the depth of 660 feet ; it was definitely recognised 

 at the level of 725 feet and is fairly numerous in the cores down to 740 feet, below 

 this level it has not been recorded. So far as I am aware, this form has not been 

 noticed by Mr. Chapman! in the recent dredgings on the reef-slopes or in the lagoon 

 at Funafuti. Dr. Brady^ states that it most affects the shallow water of coral reefs 

 and becomes rare at greater depths than 30 fathoms. 



Cycloclypens Carpenteri is found in the Main Boring between 567 and 598 feet, 



* ' Liiinemi Soc. Joum.,^ /^oology, vol. 28 (1900), pp. 17, 18, 201, 202. . 



t Mr. Chapman has since recoixled this species as of very rare occurrence in dredgings from the reef 

 slope of Pava Islet at .36 fathoms, and from Fntanga at .50-60 fathoms. A single specimen was also found 

 on the shore adhering to a reef fragment, llixl. (1902), pp. 400, 414. 



X "Challenger" Report, Zoolog}^ vol. 9 (1884), p. 22.3. 



