III.—Sedgwick Museum Notes. New Fossils from the Dufton Shales

Abstract

Zoarium composed of a group of branches of equal size diverging in a fan-shaped manner in nearly the same plane from a single short somewhat stouter stem; the branches originate and increase by repeated bifurcation, which takes place at uneven intervals proximally, and most frequently near the stem where the branches also are less regularly disposed and somewhat flexuous; but further from the base the bifureation is rare and more regular, and the distal portions of the branches are nearly straight and sub-parallel or only very slightly divergent. Zoœcial openings present only on one side; zoœcia arranged in 3–4 longitudinal rows, the outer row on each side composed of regularly disposed equidistant zoœcia of equal size and placed alternately; peristomes prominent, laterally projecting out-wards as short sharply triangular spines directed forwards and situated about one to one-and-a-half times the diameter of the branches apart; zoœcia in the one or two inner longitudinal rows without prominent peristomes, opening obliquely on the face of the branches, smaller than the lateral rows, and somewhat irregularly arranged. Reverse face of branches non-celluliferous, minutely pitted.