362 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Of the forty-seven rock-sections examined, Lithothamnion occurs in 
thirty-five, and is decidedly the most abundant and most widely dis- 
tributed organism. Many of the slides in which it is not found have 
been dolomitized, and any organisms present have been removed. Prob- 
ably Lithothamnion was present in some of these rocks originally. It 
should be mentioned that the term Lithothamnion is used throughout 
in the older and wider sense, and not as a generic name. 
Halimeda, the other calcareous alga present, is much less widely dis- 
tributed. It occurs in nine sections, coming from Mango, Niue, and 
Eua. It is much less stable than Lithothamnion, and this may account 
to some extent for its more limited distribution. 
Echinoderm fragments (largely echinoid spines) occur in seventeen of 
the specimens, and take an appreciable part in the composition of the 
rocks. Polyzoa were found in twelve slides from eight of the fourteen 
islands. They are most abundant in the Vavau rocks. 
Corals occur in fifteen sections, being represented in two cases by 
aleyonarian spicules only. Since they undergo alteration rather easily, 
they may have been present originally in some of the altered rocks, 
but even taking this into account, they play a much less important 
part in the formation of the limestones than might be expected. More- 
over, a large proportion of the rocks were obtained from terraces 
where the corals seem to be especially abundant, yet the actual bulk 
of the terraces compared with the rest of the limestones is not 
great. 
Of the Foraminifera, Carpenteria occurring in nineteen sections, and 
Polytrema in twenty-one, are the most widely distributed and also the 
most numerous individually. Carpenteria has probably had an even 
wider distribution than appears, as it seems to undergo alteration fairly 
easily. The genus Polytrema is commonly represented by P. miniaceum 
Pallas, sp., but P. planum Carter also occurs. Both forms are found at 
times intergrown with Lithothamnion, forming a mass consisting of layers 
of the different organisms alternating. Polytrema, however, encrusts 
various objects besides Lithothamnion. 
Gypsina was found in eleven sections, and is often very abundant. 
Orbitolites occurs in ten sections, but is only abundant in the Niue rocks. 
Asa rule, not more than one specimen occurs ina slide. In sections it 
possesses a burnt sienna color which is characteristic, although in some 
cases where alteration has taken place it is black and opaque. Miliolina 
occurs in eight sections, but does not make up a considerable part of any 
of the rocks. It is commonest in Eua and Vavau sections. 
