Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume V (1877-1881)
Buel, Ira M.
The corals of Delafield, pp. 185-193 PDF (2.5 MB)
188 Wlfisconsin Academy of Sciences, Arts, and Letters. the surface of some of the blocks of shale, and though their di- ameter is hardly larger than that of a knitting needle, their pecu1. iar sharp annulations distinguish them at a glance. The surface pores are fine as needle points, yet under the microscope show inl general an elliptical section and are separated by grooved walls givingto each opening a distinct margin or rim which is elevated into a sharp spine on the lower side. The genus Fistalapora ex. hibits a still further remove from the Bryozoan type. The larger cells in this series have plainly marked transverse partitions as in the Favosite corals. Still we have in some forms thin incrusting layers and masses built up by the superposition of these layers. Our collections contain several new species of this genus, two of which have been de-cribed. The two forms to which I wish to, call your attention now are Fi so7i(lissi/ma and F. lens. The sur- face markings in these species are nearly alike; the former pre- sents solid, cylindrical or flattened stems, often branching, while the latter presents disk-like expansions with openings on one side only. The surface of the former shows very small elliptical cells, separated by comparatively thick walls or interspaces which are studded by minute pores arranged in one, two, or sometimes three rows between the cells. Twelve to sixteen of these larger cells are found in the space of an eighth of an inch, measured alon1'' the branches. In F. lens the cells are rather larger and the' interspaces narrower; otherwise the appearance of the surface in these species is similar. The forms already noticed are generally considered to be Bryq. zoans. The difference of opinion that has been referred to applies Principally to the remaining forms, and at this point, therefore, we should look for some important fundamental distinctions. The genus StellZpora stands nearest to those just noted, an therefore, claims our attention. The beautiful form, S. pol stomella, is one of our most common fossils: and although we 0 tain only fragments of its broad frond like expansions, th star-like tubercles that stud its surface, when perfectly preserve render it one of the most attractive species to the casual observe Our species is identified with the form described by Nicholson the Ohio reports, but presents some points of difference. T k,'. C
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