REPORT OR THE FORAMINIFERA. 
243 
of 1882, and they form the subject of a short paper recently published in the Proceedings 
of the Royal Society ( loc . cit). 
Two specimens were secured, but owing to the excessively fragile nature of the test, 
both were much broken. The largest fragment is represented in figs, a, b, drawn to the 
natural size. This specimen is about an inch and a half (38 mm.) in diameter, and 
about eight-tenths of an inch (20 mm.) in thickness, but it is probable that the latter 
dimension may not be much more than half that of the entire organism ; indeed, it is 
evident that the test when complete was a rounded mass, which, if developed with any 
degree of symmetry, must have been a sphere of about an inch and a half diameter. The 
structure revealed by the fractured surfaces is that of a congeries of branching and 
inosculating tubes radiating from a common centre. 
The fragile nature of the investment is due to the fact that the walls are composed of 
fine sand, with scarcely a trace of inorganic cement. In this respect the organism bears 
a close resemblance to several well-known arenaceous Rhizopods, notably to Astrorhiza 
arenaria, but the difference in size renders the absence of incorporating cement a much 
more noticeable feature; for whilst the test of the latter species, though loosely arenaceous, 
has sufficient strength and substance to bear handling without injury, that of the present 
form will scarcely support its own weight when taken out of water, and crumbles into a 
mass of sand on the gentlest attempts at manipulation. 
The central portions of the test appear to consist of a network of branching and often 
contorted tubes, of somewhat smaller diameter than those of the exterior, and less regu- 
larly disposed. Nearer the periphery the system of tubes takes a distinctly radial 
character, and in a favourable section appears divided into concentric layers or tiers of 
gradually increasing depth (fig. c). The concentric “ partitions ” exhibited in the radial 
section of the test (fig. c, — cc) are not, like the “ labyrinthic layers ” of Parkeria , con- 
tinuous septa of cancellated structure, but are formed by lateral tubular branches, given off 
at intervals, which unite so as to produce a more or less regular network. As nearly as can 
be made out, there may have been ten or eleven such reticulated “ partitions,” at inter- 
vals varying from -^th inch (1/26 mm.) near the centre, to ^th inch (2'5 mm.) near the 
periphery. 
As already stated, the tubes are not of uniform size, those near the centre measuring 
sometimes no more than ^th inch (0’5 mm.) in external diameter, whilst near the peri- 
phery they sometimes exceed -^g-th inch (1 mm.), the average diameter being about 
inch (0735 mm.). Their external surface is granular, but, in the dry condition, tolerably 
smooth ; the interior is smooth and well finished. The internal cavity, whether of the radial 
tubes or the branches, is continuous, exhibiting neither constrictions, septa, nor labyrinthic 
subdivision. The thickness of the walls is about i nc h (0725 mm.). 
The peripheral ends of the tubes are rounded, and closed by an aggregation of sand- 
grains of somewhat lighter colour than the rest of the test, in precisely the same way as 
