CORALS AND BRYOZOA. 
219 
the greater space between them, and the more prominent projection from the 
posterior portion of the peristome: it may be distinguished from F. confertipora 
by the trilobate cell apertures, the denticulations and the more prominent and 
distant monticules: from F. spheroidea by the manner of growth, the smaller 
cell apertures, their trilobate form, and denticulations: from L. vesiculata by 
the prominent monticules, the less frequent cell apertures, and the nodose or 
granulose mesopores. 
Formation and locality. Hamilton group, on the shore of Canandaigua lake, 
Ontario county, New York. 
Fistulipora segregata. 
PLATE LIX, FIG. i. 
Thallostigma segregata, Hall. Trans. Albany Institute, vol. x, p. 186. 1881. 
“ “ “ Report of State Geologist for 1883, p. 27. 1S84. 
Zoarium forming thin lamellate expansions, free or incrusting other objects; the 
fronds having an observed thickness of .50 mm.; under surface a thin, wrin¬ 
kled epitheca. Cells tubular, cylindrical, gradually increasing in size to the 
aperture, arising obliquely from the epitheca, curving and opening directly 
outward. Cell apertures broadly oval or circular, length .25 mm., irreg¬ 
ularly disposed, generally separated by a space equal to or greater than the 
diameter of an aperture. Peristomes strong, distinctly and equally elevated, 
smooth on the specimens observed. Mesopores comparatively large, gene¬ 
rally two, but frequently three series between adjacent apertures; margins 
elevated slightly less than the peristomes. Surface marked by low, rounded 
monticules, the centers of which are destitute of cell apertures, and are 
distant from each other about 3 mm.; the apertures on the monticules are 
not larger than those on other portions of the frond. 
This species has a general resemblance to F. micropora, but the cell apertures 
are larger, more nearly circular and more distant from each other, and the meso¬ 
pores are larger: from F. multaculeata it is distinguished by the more broadly 
oval, nearly circular and more distant cell apertures, larger mesopores and absence 
of spinules on the peristomes and margins of apertures : from F. decipiens by the 
more broadly oval cell apertures, their greater distinctness, and the smaller 
