F. R. Cowper Reed—Fossils from Dufton Shales. 295 
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 bifurcation is rare and more regular, and the distal portions 
of the branches are nearly straight and sub-parallel or only very 
slightly divergent. Zocecial openings present only on one side; zocecia 
arranged in 3-4 longitudinal rows, the outer row on each side 
composed of regularly disposed equidistant zocecia 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; zocecia 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. 
mm. 
Dimensions. Length of zoarium . about 20°00 
Width of zoarlum . about 25°00 
Width of branches. . about 0°75 
Remarks.—We may compare this species with Cr. wilensis, Wiman,* 
from the Borkholm Beds, but the zocecia of the lateral rows in the 
latter do not project so much, and the reverse face is stated to be 
smooth. 
BRACHIOPODA. 
ORTHIS DUFTONENSIS, sp. nov. Pl. XXIV, Figs. 5-11. 
Shell sub-quadrate to transversely semi-elliptical, usually rather 
wider than long and widest across middle; biconvex to flattened ; 
valves shallow. Hinge-line straight, shghtly less than maximum 
width of shell; cardinal angles sub-rectangular to obtuse. Pedicle- 
valve sub-conical, weakly convex; hinge-area large, triangular, 
not steeply inclined, but making an angle of 60°-75° with general 
surface of valve, striated parallel to hinge-line, and crossed by rather 
narrow triangular delthyrium ; beak not incurved. Brachial valve very 
slightly convex, not so deep or conical as pedicle-valve, more or less 
flattened; faint median longitudinal depression occasionally present ; 
hinge-area narrow, triangular, about one-third the width of that of 
opposite valve and steeply inclined to it, but only making an angle of 
about 20° with general surface of its own valve; delthyrium narrow 
triangular ; beak inconspicuous, small, not incurved. Surface of 
valves regularly ornamented with 40-45 simple straight narrow 
rounded equidistant prominent radiating ribs, continuous from beak 
to margin, of equal strength, separated by equal rounded concave 
interspaces one-and-a-half times to twice the width of the ribs ; inter- 
spaces marked by numerous regularly and closely set concentric lines 
or lamelle becoming weaker or obsolete in passing over ribs. <A few 
shorter ribs, not more than 6-8 on a valve, are generally inter- 
calated, arising at one-third to one-half the length of the shell, and 
1 ‘Wiman, Bull. Geol. Inst. Upsala, 1900, No. 10, vol. v, pt. i, p. 181, pl. vi, 
figs. 12-16. 
