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 confeeta. 



SOT FIGDKBD. 



PtUicmella con/erta. 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- 



