CORALS AND BRYOZOA. 
243 
tions proceed from the posterior part, and are elevated above the peristome, 
obscuring the cell opening (pi. lx, fig. 16). In the collections made from the 
Hamilton group this is by far the most common species of Stictopora. 
This species most closely resembles S. Gilberti , of the Upper Helderberg group, 
but the branches are usually narrower, the bifurcations less frequent, the mar¬ 
gins straighter, much more gradually diverging, and are frequently notched 
or serrated: from S. ovatipora it is distinguished by its usually wider 
branches; the less nearly parallel rows of apertures, and the margins of the 
fronds are notched or serrated: from S. sinuosa, by the continuous longitudinal 
ridges: from S. gronifera, by the continuous longitudinal ridges and absence of 
granules on the ridges and peristomes: from S. palmipes, by the different man¬ 
ner of growth, narrower and thicker non-celluliferous margins, and the absence 
of nodes or spinules on the longitudinal ridges. 
Formation and localities. Hamilton group, Lodi landing, Seneca county; North 
Bristol, Ontario county; near Geneseo, Livingston county; Darien Centre, 
Erie county; Bellona, Yates county; near Norton’s landing, Cayuga county; 
near Canandaigua lake, Ontario county ; Borodino, Onondaga county, and other 
localities in Central and Western New York. 
Stictopora trilineata, n. sp. 
PLATE LXI, FIGS. 26, 27. 
Zoarium consisting of a flattened, dichotomously branched frond arising from 
a spreading base, or from several rootlets attached to foreign bodies; for 2 
or 3 mm. above the base the stipe is cylindrical and has a diameter of about 
1 mm., it then bifurcates and becomes flattened. Branches from 2 to 2.50 
mm. in width, the margins essentially parallel, scarcely expanding before 
bifurcating; non-celluliferous marginal space very narrow, width less than .50 
mm.; transverse section of a branch lenticular, greatest thickness observed 
.75 mm.; marginal angles acute; bifurcations frequently distant 10 or 12 
mm.; branches usually diverging at an angle of about sixty degrees ; on some 
of the fronds, near the base, there are occasionally lateral branches which 
diverge at an angle of ninety degrees. Cells tubular, for a portion of their 
length nearly parallel with the epitheca, then abruptly curving and opening 
