KARAKORAM STONES, OR SYRINGOSPHJERID.E. 13 



Radial 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 xwo inch, but the average size of the 

 tubes is 3^0 inch in 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 

 (jV inch to ^5 inch. (Plate I, Pigs. 4, 5, 6). 



A young specimen has the compound mammillae 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). 



SYBINGOSPHJERIA MONTICTJLABIA, variety ASPEBA, 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^ inch, that they have a very delicate wall, are 

 often varicose, and that they pass in great multitudes to the surface close together. Partner 

 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. 



SYBINGOSPH./EBIA TTJBERCTJLATA, 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 



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