On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . of demarcation between adjoiningtubes being never entirely obscured. Smaller corallites aredeveloped in variable number between those of average dimen-sions. Interspersed also in the thickness of the walls of thecorallites, or occupying their angles of junction, are numerouscircular hollow tubes, the upper terminations of which appearon the surface as the blunt spines previously alluded to. Re-mote, complete, and approximately horizontal tabulae are devel-oped in
On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . of demarcation between adjoiningtubes being never entirely obscured. Smaller corallites aredeveloped in variable number between those of average dimen-sions. Interspersed also in the thickness of the walls of thecorallites, or occupying their angles of junction, are numerouscircular hollow tubes, the upper terminations of which appearon the surface as the blunt spines previously alluded to. Re-mote, complete, and approximately horizontal tabulae are devel-oped in the tubes, being somewhat more numerous in the smallcorallites than in the larcje ones. Obs.—Not having met with any published account of thisspecies, I am not sure that it has been actually described byMr Ulrich, to whom we already owe so much excellent workon the fossils of the Cincinnati Group ; but it has been namedby him in his Catalogue of the Possils of the Cincinnati Group,and Mr Nickles has been good enough to present to me somespecimens of it. Under the circumstances, I should not have 148 THE GENUS been justified, perhaps, in treating- of it at all in this place ; andmy only apology for giving even the above short description ofits characters is, that it possesses a structural feature which Ishould have felt unwilling to have passed over without illustrates, namely, in a remarkable manner, those peculiarstructures which occur in so many of the Montimliporcu and StenoporcE, and which I havetermed spiniform , if we examine a tangen-tial section (fig, 27), we observeat the angles of junction of thenormal corallites, or between thethick walls of two adjoiningtubes, a number of clear circularspaces of comparatively large size(from i-500th to i-450th inch Fig. 27.—Tangential section of a few coral- in diameter). Some of theselites of Monticulipora implicata, Ulrich, i , i enlarged fifty times, shoeing the large!- ^Icar spaccs pr
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Keywords: ., bookauthornicholso, bookcentury1800, bookdecade1880, bookyear1881
