. The microscope and its revelations. ionbetween the chambers which they separate, resembling those which,in existing types, are occupied by stolons connecting together thesegments of the sarcode-body. Each layer of shell consists of twofinely tubulated or Nummuline lamellae. B, B, which form theboundaries of the chambers beneath and above, serving (so to spe;ik)as the ceiling of the former, and as the floor of the latter ; and ofan intervening deposit of homogeneous shell-substance C, C, whichconstitutes the inter-mediate skeleton. Thetubuli of this Xum-muline layer (fig. 643)are usually fill
. The microscope and its revelations. ionbetween the chambers which they separate, resembling those which,in existing types, are occupied by stolons connecting together thesegments of the sarcode-body. Each layer of shell consists of twofinely tubulated or Nummuline lamellae. B, B, which form theboundaries of the chambers beneath and above, serving (so to spe;ik)as the ceiling of the former, and as the floor of the latter ; and ofan intervening deposit of homogeneous shell-substance C, C, whichconstitutes the inter-mediate skeleton. Thetubuli of this Xum-muline layer (fig. 643)are usually filled up (asin the Nummulitesof the Nummuliticlimestone) by mineralinfiltration, so as sections topresent a fibrous ap-pearance ; but it for-tunately happens thatthrough their havingin some cases escapedinfiltration the tubu-lation is as distinctas it is even in recentNummuline shells (). bearing a singu-lar resemblance in itsoccasional waviiiess tothat of the crabs thickness of thisinterposed layer varies. FIG. 641.—Portion of the calcareous shell of canadense as it would appear if the serpentinethat fills its chambers were dissolved away : A1, A1,chambers of lower storey opening into each otherat «, a, but occasionally separated by a septum,b, b; A2, A-, chambers of upper storey; B, B,proper walls of the chambers, formed of a finelytubular or Nummuline substance; C, C, inter-mediate skeleton, occasionally traversed by largestolon-passages, D, connecting the chambers ofdifferent storeys, and penetrated by the arbores-cent systems of canals, E, E, E. considerably in differ-ent parts of the same mass, being in general greatest near itsbase and progressively diminishing towards its upper intermediate skeleton is occasionally traversed by largepassages (D), which seem to establish a connection between thesuccessive layers of chambers ; and it is penetrated by arborescentsystems of canals (E, E). which are often distributed both soextensiv
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
