Odontocaulis Lapworth, a synonym of Callograptus Hall

Abstract

The original generic diagnosis is as follows:—“Polypary cyathiform, composed of numerous independent and frequently bifurcating polypiferous branches, originating from the distal extremity of a short stem, which is likewise polypiferous and is terminated proximally in an irregular corneous expansion. Hydrothecae of the type of those of Dictyonema, biserial, sub-alternate.“The chief peculiarity of this genus is afforded by the character of the stem, which is identical in every respect with the main branches, and, like them, is denticulate or polypiferous throughout the whole of its extent. It commences proximally in a flattened expansion, with irregular or frayed-out edges, possibly the remains of a disk or bulb of attachment.“The mode of branching is rigidly dichotomous, the first two branches being formed by the sub-division of the main stem itself. Each arm branches and rebranches again and again in the same manner, at frequent and close intervals, composing an elegant cyathiform or fan-like polypary, very symmetrical in form. The branches retain their original width to their final division, which gives rise to two minute branches less than one-tenth of an inch in length.