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. 



FlSTULIPOKA SEGREGATA. 



PLATE LIX, FIG. 4. 



Tballostigma seffregata. Hall. Trans. Albany Institute, vol. x, ji. 186. 1881. 



Report of State Geologist for 1883, p. 27. 1884. 



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 

 outwiird. 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 ne.arly circular and more distant from each other, and the meso- 

 pores are larger : from F. multacukata 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 



