250 
PALAEONTOLOGY OF NEW YORK. 
center of the aperture. Peristomes thin, distinctly and equally elevated, 
not denticulated, sometimes finely granulose or with minute nodes. Cell 
apertures regularly disposed in parallel longitudinal rows, from six to eight 
rows on a branch, generally seven; longitudinally the apertures are in con¬ 
tact; transversely they are separated by about half the diameter of an 
aperture; the apertures of the marginal rows are only a very little larger 
than the others. The space between the rows of apertures is generally flat 
or slightly concave, with a fine angular striation along the middle; some¬ 
times smooth, at other times the whole' space is elevated and angulated; 
when well preserved the surface is finely granulose. 
Formation and locality. Hamilton group, West Williams, Province of Ontario, 
Canada. 
Stictopoka limata, n. sp. 
PLATE LX I, FIGS. 14-16. 
Zoarium consisting of a flattened, dichotomously branched frond, proceeding 
from a spreading .base attached to foreign bodies. Branches a little more 
than 1.50 mm. in width; margins parallel, the branches not widening before 
bifurcation; non-celluliferous marginal space extremely narrow, not wider 
than .20 mm.; transverse section lenticular, angles at the margins very 
acute, greatest thickness observed about .50 mm.; bifurcations compara¬ 
tively distant, branches continuing for 15 mm. or more before bifurcating. 
Cells tubular, parallel with the mesotheca for a portion of their length, then 
abruptly curving and opening directly outward. The intercellular tissue 
consists of irregularly disposed vesicles. Cell apertures oval, length about 
.15 mm., width a little more than one-half of the length, disposed in longi¬ 
tudinal parallel rows, separated longitudinally by the length of an aperture; 
transversely by twice the width of an aperture; five rows on each face of 
of the branch; the apertures of the outer rows are larger than the others, 
having a diameter of .25 mm., and are sometimes slightly oblique to the axis 
of the branch. Peristomes thin, slightly and equally elevated; there are 
occasionally slight evidences of minute denticulations from the inner face of 
