212 
PALEONTOLOGY OF NEW YORK. 
monticules extend to the center and are not larger than those on other por¬ 
tions of the frond. 
The cell apertures and mesopores of this species are very similar to F. 
ponderosa of the Lower Helderberg group, but it may be distinguished by the 
numerous monticules and the regular disposition of the vesicles, forming septate 
tubuli; the surface of that species is without monticules or maculae, the vesicles 
are irregularly disposed, and the spines on the peristomes are stronger: from 
F. variopora. it is distinguished by the more numerous monticules, the smaller 
and more nearly circular cell apertures, their closer disposition, their uniform 
size and the absence of a non-celluliferous space at the center of the monticules : 
from F. serrulata , by the more numerous monticules, the much closer disposition 
of the cell apertures and the minute mesopores: from F. scrobiculata by the 
prominent monticules, the closer disposition of the cell apertures and the 
minute mesopores. 
Formation and locality. Hamilton group, Moscow, Livingston county, N. Y. 
Fistulipora scrobiculata. 
PLATE LVIII, FIGS. 17, 18. 
Thallostigma scrobiculata , Hall. Trans. Albany Institute, vol. x, p. 184. 1881. 
“ “ “ Report of State Geologist for 1SS3, p. 20. 1884. 
Zoarium consisting of explanate, free or incrusting fronds, or of masses formed 
by the superimposition of successive layers of growth; the fronds observed 
vary from .50 to 2 mm. in thickness; the under surface consists of an 
epitheca, strongly wrinkled concentrically, and showing radiating markings, 
caused by the recumbent portion of the cell tubes. Cells tubular, for a short 
distance nearly parallel with the epitheca, but for nearly their entire length 
rectangular, or slightly oblique to the surface, invariably opening directly 
outward, walls thin, smooth; septa infrequent. Intercellular space vesicu- 
lose; near the base the vesicles are irregularly disposed, more regularly 
above, having the appearance of septa dividing the space between the cell 
apertures, and occurring at irregular intervals, sometimes four or five in the 
space of 1 mm , at other times only one or two. Cell apertures circular, 
