KAEAKOEAM STONES, OE SYEINGOSPHiEEIEA]. 
13 
Eadial sections show the radial series of tubes to bifurcate or inosculate frequently, and 
to increase in size in varicosities. These tubes mainly go to the surface and open there 
directly; and some of them give off branches on all sides to form the interradial tube 
reticulation. As much of this reticulation consists of radiating tubes, the last series of them 
opens at the surface. The tubes of the outer meshes are also represented at the surface by flat 
or bent tubes. The interradial series thus formed separates, very distinctly, the wide conical 
radial congeries from each other. Almost every mammilla has its radial congeries of tubes. 
The diameter of the smallest lateral tubes given off is inch, but the average size of the 
tubes is 3^0 diameter. Near the surface there are occasionally great differences in the 
size of the tubes, many of which become flat, and the same spreading out is seen further in, 
where the granular element of the tube-wall has been formed in excess. 
The typical specimen is inch high and 1 inch broad. The diameter of the pores is 
^^0 inch to inch. (Plate I, Pigs. 4, 5, 6 ). 
A young specimen has the compound mammillse hardly formed, but the single ones and 
the pores are abundant. It is more spheroidal than the type (Plate I, Pigs. 7, 8 , 9). The 
magnified radial sections (Plate III, Pigs. 1, 8 , 9) were taken from this form. 
A variety of the species has a larger body than the type (Plate I, Pigs. 10, 11, 12), but 
the mammillae are low and insignificant. The magnified oblique section, showing the diver¬ 
gence of the very open tube series (Plate III, Pig. 4), is from this form, as is also the top of a 
monticule showing tubes and tube openings (Plate III, Pig. 3). 
Syeingosph^hia montioulaeia, variety aspeea, Duncan. Plate II, Pigs. 6 , 7. 
This transitional variety has very few compound mammillae, but a great number of 
single ones and pores. It is a large form, and is oblately spheroidal, about 1 inch in height 
and 2 inches in breadth. It was collected by Colonel Godwin-Austen, and is introduced here 
in exemplification of the series. 
The radial section shows that the radial congeries are very widely separated by reticulate 
tubulation ; that the tubes are large, usually - 3^0 inch, that they have a very delicate wall, are 
often varicose, and that they pass in great multitudes to the surface close together. Parther 
in, the intertubular space equals the diameter or the tubes, and gives rise to much confusion, 
and it is difficult to know, except by reflected light, which is tube and what is calcite 
infiltration. 
In some parts the tube reticulation is close, and the tubes crowded together, and in this 
there is an approximation to the next species. 
Syeingosph^eia tubeeculata, Duncan. Plate II, Pigs. 1, 2. 
The body is spherical and symmetrical in shape, and is covered with numerous low, 
rounded, broad elevations, separated by indistinct interspaces. There are minute pores 
scattered over the whole surface. The eminences about inch across at their base, are not 
^ of that measurement in height; they are sometimes irregularly shaped. In some parts 
the interspaces are as broad as the bases of the eminences, but usually the slope of one 
eminence merges into that of another, the interspaces being confined to the concavity. The 
interspaces are covered with a very crowded and close arrangement of the tubes; many 
