Abstract

Several specimens of Metriophyllum gracile collected from a locality in the type area (middle Devonian) in the Eifel region, Germany, show a distinct groove extending from the apical end about one-third the length of the corallum. It is suggested that the groove formed with the growth of the coral as a result of being anchored to a stem such as a seaweed which decomposed leaving no trace. Specimens from other localities in the same area and at the same horizon show either a bulbous expansion or a rootlike process for attachment. Also noted is a change in form from trochoid to nearly cylindrical where the corallum attains maximum diameter, and a shift from the longitudinal ridges at the apical end to more prominent growth striations at the distal end, with a constriction at the junction. No change in relative rate of growth could be detected, but there seems to have been a pause at the point of maturity.

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