. The microscope and its revelations. ernal whorl; b, one of the outer row of chambers ; c, c, whorl investedby a , (I, one of the chambers of the fourth whorl from the margin ; e, <•,marginal portions of the inclosed whorls; /, investing portions of outerwhorl; g, </, spaces left between the investing portion of successive whorl* ;h, h, sections of the partitions dividing these. examples of the genus ; thus in some, as J. distant, they keep theirown separate course, all tending radially towards the centre: inothers, as .T. /trr!</nt«, their partitions inosculate with each other, soas
. The microscope and its revelations. ernal whorl; b, one of the outer row of chambers ; c, c, whorl investedby a , (I, one of the chambers of the fourth whorl from the margin ; e, <•,marginal portions of the inclosed whorls; /, investing portions of outerwhorl; g, </, spaces left between the investing portion of successive whorl* ;h, h, sections of the partitions dividing these. examples of the genus ; thus in some, as J. distant, they keep theirown separate course, all tending radially towards the centre: inothers, as .T. /trr!</nt«, their partitions inosculate with each other, soas to divide the space intervening bet \veen each layer and the nextinto an irregular network, presenting in vertical section the appear-ance shown in fig. 6,U ; whilst in .A, yarfinsciixis they are broken NUMMULITES 833 up into a number of chamberlets having little or no direct communi-cation with each other. Notwithstanding that the inner chambers are thus so deeplyburied in the mass of investing wholes, yet there is evidence that. FIG. 632.—Portion of a thin section of Nitinniiilitr.* l^-r/ijutu taken in thedirection of the preceding, highly magnified to show the minute structureof the shell: , a, portions of the ordinary shell-substance traversed by-parallel tubuli; b, b, portions forming the marginal cord, traversed bydiverging and larger tubnli; c, one of the chambers laid open; d, de which they contained were not cut ofl fromcommunication with the exterior, but that they may have retainedtheir vitality to the last. The shell itself is almost every-where minutely porous, being penetrated by parallel tubuli, whichpiiss directly from one surface to the other. These tubes are divided lengthwise by a vertical section, in fig. 632, «, a ; whilstthe appearance they present when cut across in a horizontal sectionis shown in fig. 633, the - « ! •I. transparent shell-substance a, «, « being closely dotted with min
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
