CORALS AND BRYOZOA. 
251 
the peristomes. Rows of apertures separated by prominent, rounded, smooth 
ridges, having twice the width of the cell apertures. 
Formation and locality. Hamilton group, Darien Centre, N. Y. 
Stictopoea subrigida. 
PLATE LX, FIG. 21. 
Stictopora subrigida, Hall. Trans. Albany Institute, vol. x, p. 190. 1881. 
“ “ “ Report of State Geologist for 1883, p. 43. 1884. 
Zoarium consisting of a flattened, dichotomously branched frond; the base is 
composed of several rootlets, which are attached to foreign bodies; for a 
short distance from the base the stipe is broadly oval, not expanding before 
bifurcating; branches about 1.50 mm. in width, margins parallel; trans¬ 
verse section lenticular, greatest thickness observed .75 mm.; non-cellu- 
liferous marginal space narrow, margin frequently crenulated; bifurcations 
comparatively very distant, sometimes occurring at intervals of 15 mm. or 
even more; branches diverging at an angle of about sixty degrees. Cells 
tubular, for a portion of their length nearly parallel with the mesotheca, 
then abruptly turning and opening directly outward. Intercellular space 
occupied by irregularly disposed vesicles. Cell apertures circular, minute, 
diameter .10 or .12 mm., somewhat pustuliform, disposed in parallel longi¬ 
tudinal rows, five or six on each face of the branch; apertures separated 
longitudinally by more than twice their diameter. Peristomes thin, slightly 
and equally elevated, not denticulated on the specimens observed. Ranges 
of apertures separated by prominent, rounded ridges, having a width greater 
than the diameter of an aperture, and forming the most prominent feature 
of the frond. 
4^ 4^ 4^ 4^- 4^ V- .a/* 
VV A~ A~ "A~ "A' "VV "TV 'A' -/V 
Formation and localities. Hamilton group, near Middleburg, Schoharie county, 
and railroad cutting, two and a half miles east of Alden station, Erie county, 
N. Y. 
