On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . ICULIPORA. fig. \d), many of the spines become so far aborted that theircentral cavities are no longfer to be detected, while othersattain their full development. These aborted spiniformcorallites appear to be in general what Dybowski has called* Wandstrange, though he has apparently included otherstructures as well under this name. As these aborted spinesappear, however, in forms of very different affinities (such asM. tumida, Phill., and AL Girvanensis, Nich.),
On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . ICULIPORA. fig. \d), many of the spines become so far aborted that theircentral cavities are no longfer to be detected, while othersattain their full development. These aborted spiniformcorallites appear to be in general what Dybowski has called* Wandstrange, though he has apparently included otherstructures as well under this name. As these aborted spinesappear, however, in forms of very different affinities (such asM. tumida, Phill., and AL Girvanensis, Nich.), it seems clearthat they are of no classificatory weight, whatever view wemay take as to their real nature. Lastly, if we admit the probable correctness of the viewshere advanced, we have a very interesting analogy establishedbetween certain forms of Monticulipora and some of the spe-cies of Stenopora, Lonsd., in which structures of a preciselysimilar nature occur. Thus, if we examine a tangential sectionof Stenopora Tasmattiensis, Lonsd., taken just below the sur-face (fig. 6), we see that the surface-spines are continued in-. Fig. 6.—A, Vertical section of a few of the corallites of Stenopora Tasmaniensis, Lonsd., inthe final portion of their course, enlarged twenty times, showing the annular thickeningsof the tubes and the remote tabula; B, Tangential section of the same, taken just belowthe surface, similarly enlarged, showing the transversely divided spiniform corallites be-tween the ordinary tubes. Carboniferous, Australia. wards precisely as they are in Monticulipora monili/oimis andallied types, while they are similarly composed of concentric- GENERAL AND COMPARATIVE STRUCTURE. 49 ally disposed lamellae of dense sclerenchyma. The centralcavities of the spines seem, however, to be more or less com-pletely obliterated with age; and the corallites in the outerportion of their course (fig. 6) exhibit the annular thickeningsof their walls which are so characteristic of the
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Keywords: ., bookauthornicholso, bookcentury1800, bookdecade1880, bookyear1881
