On either side of the serpentine band is the nummuline or proper wall, showing under a low power a milky appearance, which, with a higher power, becomes resolved into a tissue of the most beautiful parallel threads, representing the filling of its tubuli. Nothing can be more distinct than the appearances presented by this wall and a chrysotile vein, under every variety of magnifying power and illumination; and all who have had an opportunity of examining my specimens have expressed astonishment that appearances so dissimilar should have been confounded with each other. On the lower side two indentations are seen in the proper wall (_c_). These are connected with the openings into small subordinate chamberlets, one of which is in part included in the thickness of the slice. At the upper and lower parts of the figure are seen portions of the intermediate skeleton traversed by canals, which in the lower part are very large, though from the analogy of other specimens it is probable that they have in their interstices, and at their branching extremities, minute canaliculi not visible in this slice. Fig. 2, from the same specimen, shows the termination of one of the canals against the proper wall, its end expanding into a wide disc of sarcode on the surface of the wall, as may be seen in similar structures in modern Foraminifera. In this specimen the canals are beautifully smooth and cylindrical, but they sometimes present a knotted or jointed appearance, especially in specimens decalcified by acids, in which perhaps some erosion has taken place. They are also occasionally fringed with minute crystals, especially in those specimens in which the calcite has been partially replaced with other minerals. Fig. 3 shows an example of faulting of the proper wall, an appearance not infrequently observed; and it also shows a vein of chrysotile crossing the line of fault, and not itself affected by it--a clear evidence of its posterior origin. Figs. 4 and 5 are examples of specimens having the canals filled with dolomite, and showing extremely fine canals in the interstices of the others: an appearance observed only in the thicker parts of the skeleton, and when these are very well preserved. These dolomitized portions require some precautions for their observation, either in slices or decalcified specimens, but when properly managed they show the structures in very great perfection. The specimen in Fig. 5 is from an abnormally thick portion of intermediate skeleton, having unusually thick canals, and referred to in a previous chapter. Such additional peculiarities and specialties might be multiplied to any extent from the numerous prepared specimens now in our collections.