244 
THE VOYAGE OF H.M.S. CHALLENGER. 
in Astrorhiza arenaria and its immediate allies. These are shown in the side view (fig. 
a), at the spot marked aa. 
The tubes of some parts of the test were filled with dark-coloured sarcode, si m ilar in 
all respects to that found in the tests of many of the larger arenaceous Foraminifera. 
Chemical analysis shows that upwards of 53 per cent, of the dry test consists of sili- 
ceous sand, and about 35 per cent, of carbonate of lime. The latter item may be 
accounted for by the presence of a very large number of minute Foraminifera amongst 
the sand of which the test is built ; of secreted calcareous matter there appears to be 
little or none. 
The precise habitat of the specimens is given in the following note from the log of 
the “ Triton ” : — 
“Station 11. August 28th, 1882, lat. 59° 39' 30" N., long 7° 13' W.; depth, 555 
fathoms; ooze; surface temperature, 57°‘2 ; bottom temperature, 45°'5 F.” 
The position is to the west of the Wyville-Thomson Ridge, and close to the “Holtenia 
Ground ” of the “ Porcupine ” Expedition. 
Mr. Murray states that a somewhat similar specimen was dredged at a depth of 1000 
fathoms off the Azores, during the Challenger cruise, but that it went to pieces in the 
sieve. 
Sub-family 2. Pilulininse. 
Pilulina, Carpenter. 
Pilulina, Carpenter [1870], Brady. 
The genus Pilulina is at present limited to a single species, as follows. 
Pilulina Jeffrey sii, Carpenter (PI. XXY. figs. 1-6). 
Pilulina, sp., Carpenter, 1870, Descr. Cat. of Objects from Deep-sea Dredgings, p. 5, No. 5. 
Pilulina Jeffrey sii, Id. 1875, The Microscope, 5th ed., p. 532, figs. d.,e. 
Test free, nearly spherical ; consisting of a single undivided chamber, the walls of 
which are composed of felted sponge-spicules and fine sand with no calcareous cement. 
Aperture a long curved or sigmoid slit, with slightly raised lips. Colour light grey or 
nearly white. Diameter, -fth inch (3‘5 mm.). 
This species is perhaps the best type of the series to which it belongs, and exhibits in 
as marked a manner as any the peculiarities of structure which constitute the salient 
feature of the entire Sub-family. Evidences of selective power, in respect of the extraneous 
substances employed in the construction of the test, are not uncommon amongst the 
arenaceous or composite types of Foraminifera ; and nowhere is this faculty more 
