202 MR. F. CHAPMAN ON FORAMINIFERA 
History’ Museum, South Kensington, confirms the identity of 
the two forms. 
This organism, as I have already shown, is of great importance 
as a rock-builder, by forming concentric encrustations round 
fragments of coral and alge. It also plays an important part 
in cementing loose fragments together, by filling crevices and 
eventually enwrapping several fragments, until they form a 
solid conglomerate. 
In the lagoon P. planum is found binding together the 
separate fronds of Halimeda as they lie on the lagoon-foor. 
It is impossible to distinguish P. planwm in the lagoon material 
without the aid of thin sections made from the accreted fragments 
for microscopic examination. 
Lagoon, Funafuti. Sample 6 (21 fathoms); sample 10 (26 
fathoms); sample 11 (25 fathoms); sample 12 (23 fathoms) ; 
sample 14 (16 fathoms). 
Family NUMMULINID. 
Subfamily PoLYSTOMELLING. 
Nonronina, d'Orbigny [18261. 
NONIONINA DEPRESSULA (Walker & Jacob). 
Nautilus depressulus, Walker & Jacob, 1798, Adams’ Essays, Kan- 
macher’s ed., p. 641, pl. xiv. fig. 33. 
Nonionina depressula (W. & J.), Egger, 1893, Abhandl. bayer. Akad. 
Wiss., math.-phys. Cl. ii. vol. xvii. p. 427, pl. xix. figs. 38, 39. 
This species is rare in the lagoon. 
Lagoon, Funafuti. Sample 13 (26 fathoms): sample 18 (73 
fathoms). 
NonrIONINA UMBILICATULA (Montagu). 
Nautilus umbihcatulus, Montagu, 1803, Test. Brit. p. 191; Suppl. 
p. 78, pl. xviii. fig. 1. 
Nonionina umbilicatula (Montagu), Egger, 1893, Abhandl. bayer. Akad. 
Wiss., math.-phys. Cl. ii. vol. xvii. p. 426, pl. xix. figs. 36, 37. 
This species is more numerous than the preceding, and the 
specimens are as a rule typical. 
Lagoon, Funafuti. Sample 1 (10 fathoms); sample 4 (28 
fathoms); sample 7 (24 fathoms); sample 8 (26 fathoms) ; 
sample 11 (25 fathoms). 
