292 On the Structure and Position of Eozoon Oanadense. 



of the calcareous shell, standing side by side, like the fila- 

 ments that form the "pile" of velvet, their lower ends 

 resting- on the subjacent segment, whilst their upper form 

 a uniform surface so close in texture as to be with difficulty 

 resolvable into the points of its constituent aciculi (Uncoloured 

 Plate, Fig. 2, a). This residuary layer (when not thrown off, 

 as it often is, by the disengagement of gas in the process of 

 decalcification) is at once distinguished by its whiteness ; as is 

 shown at the upper part of the Coloured Plate on the surface of 

 the segments, and at the lower in the section of the lamellae. If 

 a small portion of it be detached with the point of a needle, it is 

 easily shown to be composed of the most delicate asbestiform 

 fibres, each of them representing the original pseudopodium 

 of sarcode which passed through the tubule. But, as I have 

 shown to be often the case in Operculina,* the tubulimay depart 

 from their normal parallelism, separating from each other in 

 some parts, and becoming more closely crowded in others ; so 

 that instead of the uniform punctation which the internal 

 surface of the chamber-wall exhibits, we may find great 

 diversities in the disposition of their external orifices, these 

 being often congregated in bands and clusters, with intervals 

 of non-tubular shell-substance between them. A yet greater 

 variety in their course presents itself in Eozoon. For the in- 

 tervals of non-tubular shell-substance left in some parts of the 

 chamber-wall by the crowding- together of the tubules in others, 

 . are marked in the decalcified layer of asbestiform fibres by 

 fissures in the " pile" (Fig. 2, 6), such as would be made in the 

 surface of a piece of velvet by doubling it back so as to 

 separate the free ends of the filaments ; whilst the convergence 

 of the intervening fibres often unites them into minute flat- 

 tened leaf-like tufts. A more marked degree of the same 

 convergence, bringing the greater number of the pseudopodia 

 proceeding from each segment into one bundle (Fig. 2, c), is not 

 unfrequently seen in parts in which there has been a great 

 development of the " intermediate skeleton" presently to be 

 described; and a portion of the asbestiform layer in which 

 this arrangement is well exhibited, constitutes, under the 

 Binocular Microscope, one of the most beautiful objects with 

 "which I am acquainted, every individual thread glistening 

 brightly under appropriate illumination, and holding its own 

 proper place, while an infinite variety of detail is shown in the 

 arrangement of the brush-like bundles, of which no two are 

 precisely similar. Another variety in the disposition of the 

 tubuli is one to which I have seen no parallel in other Fora- 

 minifera. Betaining their separate parallelism, they some- 



* Memoir on Operculina in the Philosophical Transactions for 1859, p. 24, 

 and Plate IV., figs. 2, 4 ; also, Introduction to the Study of the Foraminifera, p. 256. 



