CORALS AND BRYOZOA. 
281 
ing, afterward continuing of essentially the same width, bending abruptly 
outward near the extremity, the apertures being nearly circular, and having 
their margins parallel with the axis; during the growth the margin is 
rectangnlar to the axis. Cells generally alternating, but sometimes occur¬ 
ring irregularly, very often regularly distant on the same side of the branch 
about 2 mm. Surface marked by extremely line, transverse striae, and fre¬ 
quently by strong annulations, which are more prominent on some tubes 
than on others, and sometimes are entirely wanting; the line striations 
invariably occur, and there are faint indications of longitudinal strim. The 
angle of divergence of the cell tubes from the axial tube is variable, some¬ 
times being forty degrees, at other times the cells are parallel with and 
partially cover the primary axis, overlapping each other; in this condition the 
axial tube is obscured, and the frond has somewhat the appearance of con¬ 
sisting of two parallel lines of cell tubes with the apertures opening outward. 
This species can be distinguished from other forms of this genus by its much 
larger size. 
Formation and locality. Hamilton group, York, Livingston county, N. Y. 
HERNODIA, Hall. 1881. 
Hernodia humifusa. 
PLATE LXV, FIGS. 20, 21. 
H&'iiodia humifusa, Hall. Trans. Albany Institute, vol. x, p. 196. 1881. 
“ “ “ Report of State Geologist for 1883, p. 58. 1884. 
Zoarium parasitic, procumbent, consisting of tubular cells ; increasing by lateral 
gemmation; from one to three buds from each cell. The cells have a length 
of 5 mm., gradually enlarging to the aperture, diameter at the smaller end 
.35 mm., the greatest diameter of 1 mm., is at .50 mm. from the aperture. 
Apertures slightly constricted, not elevated, rectangular to the axis of the 
cell on the specimens observed; transverse section sub-circular; attached 
surface flattened, upper surface convex. After budding the parent cell 
continues its growth frequently for the extent of 1.50 mm. or even more. 
