CORALS AND BRYOZOA. 
279 
tubular cells, and occasionally tubular extensions having the same manner of 
growth as the primary axis. Fronds comparatively large, some specimens 
entirely cover the exterior of Cyathophylloid corals, which have a length of 
75 mm., and a diameter at the calix of 45 mm. Axial tube and lateral cells 
sinuous or tortuous, diameter a little more than .50 mm. ; length of cells 
generally from 1 to 1.25 mm.; just before ceasing growth the cell tubes 
turn abruptly outward, the apertures being parallel with the axis of the 
branch and constricted, the width a little more than one-half the length. Cell 
tubes sometimes alternating, at other times occurring opposite to each other, 
rapidly expanding for a short distance, but for the greater portion of their 
length essentially of the same size; those on the same side of the axial tube 
are quite regularly distant from each other 1.50 mm. One side of the cell 
for its entire length is very frequently in contact with the axial tube and 
the base of the succeeding cell tube, the frond presenting a compact appear¬ 
ance, but others diverge at an angle of forty-five degrees. The axial tubes 
and lateral cells are sharply striated and wrinkled transversely, and when 
well preserved have numerous, very fine, longitudinal striations; on some 
cells there are evidences of a line of nodes along the middle. 
This species may be easily distinguished from Hederella cirrhosa by the much 
larger size of the cell tubes, those of that species having a diameter of only .20 
mm., and a proportionally closer arrangement; it is intermediate in size between 
H. Canadensis and H. magna ; from the former it may be distinguished by the 
greater diameter and lesser length of the cell tubes, and from the latter by its 
more slender form and less compact appearance. 
Formation and localities. Hamilton group, York, Livingston county; near 
Canandaigua lake, Ontario county, N. Y., and near Arkona, township of Bosan- 
quet, Ontario, Canada. 
Hederella conferta. 
NOT FIGURED. 
Ptilionella conferta , Hall. Trans. Albany Institute, vol. x, p. 195. 1881. 
“ “ “ Report of State Geologist for 1883, p. 56. 1884. 
Zoarium parasitic, usually occurring on Cyathophylloid corals, most frequently 
on Heliophyllum Haiti; procumbent, attached for its entire extent; con- 
