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 

 rectangular 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 fine, transverse striae, and fre- 

 quently by strong annulations, which are more prominent on some tubes 

 than on others, and sometimes are entirely wanting ; the fine striations 

 invariably occur, and there are faint indications of longitudinal striae. The 

 angle of divergence of the cell tubes from tlie 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. 



Hernodia humifusa. Hall. Trans. Albany Institute, vol. x, p. 196. 1881. 



Report of State Geologist for 1883, p. 58. 1884. 



ZoARiCM 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. 



