CORALS AND BRYOZOA. 
277 
Formation and localities. Hamilton group, Hopeton, shore of Seneca lake, 
Yates county, and in the Genesee Yalley, Livingston county, N. Y. 
HEDERELLA, Hall. 1881. 
Hederella cirrhosa. 
PLATE LXV, FIGS. 12, 13. 
Hederella cirrhosa, Hall. Trans. Albany Institute, vol. x, p. 194. 1881. 
“ “ “ Report of State Geologist for 1883, p. 53. 1884. 
Zoarium consisting of a filiform, tubular axis, from which proceed laterally 
simple tubular cells, and at irregular intervals other tublues having the same 
manner of growth as the main axis; parasitic, procumbent, attached for 
its entire length, occurring on Cyathophylloid corals, Brachiopoda and 
Crinoid columns. Cells about 1 mm. in length; diameter .20 mm.; trans¬ 
verse section nearly circular, turning abruptly outward at the extremity, the 
aperture being parallel with the axis of the branch and circular, generally 
alternating, distant on the same side of the branch from 2 to 2.50 min., 
though sometimes occurring at irregular intervals. Surface marked by 
transverse striae and angular annulations. 
This species may be easily distinguished from others of this genus by its 
much more slender, filiform character. 
Formation and locality. Hamilton group, York, Livingston county, N. Y. 
Hederella Canadensis. 
PLATE LXV, FIGS. 1-8, 14 and 16 ? 
Alecto? Canadensis, Nicholson. Canadian Naturalist, vol. vii, No. 3. 1S74. 
Aulopora? Canadensis, Nicholson. Pal. Prov. of Ontario. 1874." 
Hederella “ Hall. Trans. Albany Institute, vol. x, p, 194. 1881. 
“ “ “ Report of State Geologist for 1883, p. 53. 1884. 
Zoarium parasitic, procumbent, attached for its entire length ; usually occurring 
on Corals or Brachiopoda, most frequently on Fleliophyllum Halli. It consists 
of a primary cylindrical, tubular axis, which has lateral tubular cells at fre¬ 
quent intervals, and occasionally cells having the same manner of growth as 
the primary axis. This mode of growth is indefinitely continued so that large 
