. Bulletin - United States National Museum. Science. 50 BULLETIN 65, UNITED STATES NATIONAL MUSEUM. branches averaging 2 mm. in breadth for the larger and 1 mm. for the smallei; toward the margin of the frond, where the branchlets end in two (sometimes three) extensions of unequal thickness. Texture corneous, with the surface composed of scaly fibers. Extending longitudinally through the stipes are central or subcentral elevations (sometimes depressions), indicating a solid central axis. This species is described on two specimens, one of which shows the origin and base of the radiating branche
. Bulletin - United States National Museum. Science. 50 BULLETIN 65, UNITED STATES NATIONAL MUSEUM. branches averaging 2 mm. in breadth for the larger and 1 mm. for the smallei; toward the margin of the frond, where the branchlets end in two (sometimes three) extensions of unequal thickness. Texture corneous, with the surface composed of scaly fibers. Extending longitudinally through the stipes are central or subcentral elevations (sometimes depressions), indicating a solid central axis. This species is described on two specimens, one of which shows the origin and base of the radiating branches, and the other the general frond, although the radicle is concealed. The extreme width of the typical specimen is 14 cm., and the height 8 cm. In general form this spe- cies differs from /. plumulo- sus in that the branches are ^WIHJHIVfK^M #/ll#S9V nVK# more slender and rise regu- ^"^^-VmItJllii^A#/jRr3&.Mt^i larly and more abundantly ^.^ , ,__ __ —I,— .—, from the sides of the main V^vi/\^(^^jP^Pj]^ J^lBK^^^^Mt Ktiiies, which radiate trom a common origin and do not consist of groups of individ- ual fronds. The radicle ap- pears to have been attached to some rocky surface iu the sea, and not to have grown on some muddy bot- tom. The cell-bearing stipes appear to have had a com- mon canal, through the cen- ter of which was a central solid axis, as is also indi- cated in 7. cervicornis. FIG. li^^MULuscs SPENCER. SPECIMEN formation (uid IN U. S. National Museum. These specimens were ob- tained in the shaly dolomites, below the " chert beds" of the Niagara formation at the " Jolly-cut," Hamilton, Ontario. Doctor Gurley's notes are as follows: Polypary, in the single specimen seen, rising from a stem which gives off, in the proximal half of the portion visible, vei'y few branches which, moreover, do not rebranch into a bushlike form, the bushlike branching occurring only in the distal half of the polypary. The only prox
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Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
